This actually makes me appreciate the USB standard. Not only the fact you can just plug anything into it and expect it to work 99,9% of the time without any additional input, but also the fact that everyone just agreed that this is something we're going to be using on just about everything.
@@BritishBeachcomber It was a godsend for printers, especially in a house where you didn't need to have the printer plugged in all the time. I don't miss parallel ports at all. And most keyboards and mouses were still PS/2 in the earlier days, at least around 1999/2000. I feel like you had to go out of your way to find a USB keyboard or mouse, and there wasn't much point to doing so, since nearly all mobos still had the two necessary PS/2 ports.
@@billyeveryteen7328 yea parallel ports are something alright. I have barely used it ever outside of VM, and emulation purposes. It's still annoying to use even in that scenario.
Not unreasonable. If I buy cheap Chinese 1time USB sticks, I need to check every stick for forgery with f3 - fight Flash Fraud. With Linux I use 12 port hubs and 50 sticks a limit. Depending on the PC I cannot use that many. With an i3 the USB3 windows device limit was 8! With a XEON 50 worked slowly. With my 4600h 50 no issue
My favorite thing is when the system just starts kicking devices off. It's like the computer's hosting a house party and way too many people start showing up, until the host just loses their shit and starts throwing people out. "I said you could bring a plus one, not a plus thirty-one, get out!"
For those who don't know, USB Tree View is the OP GOAT program for this stuff. It shows you all connected devices and their level so that you can diagnose issues. If you've ever had the annoying reconnecting USB device that keeps chirping its connection sound on and off, this is the tool to use. It'll highlight funky devices just as it did in this video.
@@sophiophile Google what a validation engineer does, different than verification, emulation & testing. So there's 4 different job roles to ensure something is working.
Every so often I get re-amazed by USB. I started using computers near the end of the 80s on a DOS machine and the hot-swappable, plug and play nature of USB really changed the game.
@@lukethmpsn For real. I still remember days when you bought new phone and almost every one of them had different power supply plug, you could buy those junky power supplies with full palette of plugs that usually broke after couple uses. Those were the times
Not only data but power too. Not too long ago every small low voltage/amperage device used a little barrel jack connector or some proprietary thing for cell phones. If you were lucky you'd be able to find that one wall wart from some device you may or may not have had years ago. And even if you found one that matched the voltage and jack size you'd still have to squint and see if the jack polarity was correct. All small battery chargers used to require a wall outlet and low voltage hobby stuff like small wind/solar was a hassle because everybody did it a different way so wrangling your charge controllers was much more of a pain. Now it's all 5v over USB. If it's small and cheap it'll probably take USB. Even if USB charges slower than some of the older methods because of massively improved modern lithium batteries you'll still probably be charging it less. Things are so much easier now.
@@axelxanI still have boxes full of Nokia cables that came with the unlocking box 😅 It wasn't the only one making a different cable for each but man, it was the most
i stopped working in traditional IT departments way before it was "cool" this channel is a gem for old timey IT guys who miss the crazy IT department shenanigans we would do in the server room on off days. thanks for these!
If anyone is looking for the software Linus is using to list the devices plugged in, its called "USB Device Tree Viewer". Made by some german person called Uwe Sieber :)
Linus did a good job explaining the different limitations imposed by the USB spec, but there is one more he didn't talk about: time. More specifically, scheduling of the USB request blocks inside a USB frame that's sent out, at most, once every millisecond (in the case of USB 2.0 at least, don't know if they raised it in later versions, but I don't think so). He mentioned the four types of endpoints: ones for configuration (Control), rapid but short message transfer (Interrupt), large data (Bulk) and continuous transfer (Isochronous). What he didn't talk about is that you can't just mix'n'match them willy-nilly, because there's a limit of how much of the frame each of these types of endpoints IN TOTAL are allowed to occupy. For instance, IIRC the limit for Interrupt types is 10%. This endpoint type is used by keyboards, mice, game controllers etc., so if you only have these devices in your system, you will effectively only be able to use at most 10% of the full bandwidth of USB.
I don’t know what’s more impressive, the fact it (almost) handled 127 USB devices, or the fact they were able to find 127 devices around the office that hadn’t already been stolen (as we’ve seen is a common theme from $5000 tech upgrade videos.)
There is a trick, on each side of the usb stick are 2 squares. If they are filled with plastic or something it’s the bottom side, if they are empty its the top side
I think the fact that you could plug in more than 128 devices is a relatively recent thing potentially starting at the 3000 series CPUs. I was running into USB issues on first gen Ryzen and I wasn't anywhere close to those numbers and I was having many of my peripherals turn off and then turn back on like they were reset on the addressing end. I added an internal USB controller card and that completely solved my issue.
And that’s like…. One of the things they actually fixed lol. I couldn’t imagine having a USB device not working because of the parts I have. At least when USB was introduced, stuff still worked and they most likely shipped with a floppy disc for the driver
@@roots4x Dude no. Physical media exists to preserve things. If companies stopped making physical media including drivers, then there would be most lost media and also more older hardware thats useless cuz the driver was never archived or was deleted.
@@Thewaterspirit57 it’s almost assuredly easier to find drivers online or from your personal archives than from a floppy disk somewhere. You can easily dedicate a$5 USB drive to driver storage, or have a backup for another $5. It’s a huge waste of resources to ship a floppy drive to every customer in the age of the internet.
@@roots4x Bro, those cloud servers likely use USB ports one way or another. Just because we dont see the Cloud doesnt mean its not somebody else's physical media or computer
@@arnabbiswasalsodeep today's small systems have more oomph than the big systems from when Unix was created. The big difference was I/o channels. You don't need those now thanks to things like iscsi, but back in the day, you had to attach it to the system, e.g. DASD on block mux connectors for disks and tape drives.
@@U1TR4F0RCEBlock devices under Linux are still lettered (sda, sdb, ...) but when more then 26 a present another letter gets added (sdx, sdy, sdz, sdaa)
I love how it just turned into a Techquickie episode half way through, even thought they had gone onto a green screen until Linus grabbed a hub from the table lol
Some powered hubs also had this rather dangerous flaw in that it connects directly to the VBUS pin to the host, so it can backfeed the power to the computer, which can damages the controller and sometimes the entire computer if it was a laptops or all in ones. BigClive has a video about this that explains it pretty well.
I had one of those, it was trippy. Wasn't a big deal if the USB ports remained active when the system was off. Unplugged though, that was whack and I did not like that thing because of it. It was one of those "optionally powered" hubs though, and I'm sure those are the main ones that are notorious for it, which is sad cus a couple of diodes are all that would be needed to prevent the backfeed.
BigClive did mentioned that many cheap USB charger tester with a socket can be “backfed” and it would light up, I have a couple that also have the same behavior, so that’s a good way for quickly test a USB hub for backfeeding flaw, so far I found 2 hubs that have the backfeeding problem.
Wow, imagine being so stingy that you wont put a simple $0.02 diode to protect the PC. (technically 1N5399G costs $0.012 when bought in bulk, so even cheaper than $0.02).
If I'm not mistaken the CPU polls each device many times a second as well, so that's a good amount of CPU overhead. I wouldn't be surprised if there's significant delay between pollings and some devices not liking that.
@@ptamogyeah >1kHz peripherals don't make any sense unless you're actually a pro and you've got a 360Hz+ monitor, consistent fps higher than the refresh rate, and optimized all the low hanging software settings. even going from 1kHz to 8kHz that's shaving only 0.875ms off input lag...
I believe the actual polling is done by the USB Host Controller, not the System CPU. When there is a result from the poll, when say a key is pressed or mouse movement occurs and so on, there could be CPU overhead servicing that, though.
@GeekProdigyGuy they make plenty of sense. The higher the peripheral refresh rate, the more consistency between each individual mouse movement. They matter mostly for quick precise actions such as gaming.
USB does a lot of polling, so when there is a ton of devices, each gets a chance to speak, which slows things down. Even if they are low load devices. You also may need to wait for everything to handshake and initialize after you connect them for a WHILE, then see better stuff working.
It was scripted but then the writer happened to grab an AMD machine which reacted completely differently to this experiment than the Intel machine he did all his testing on. Most ltt videos are basically scripted down to the word. Some are partially scripted and partially off the cuff and then there's ones like this where it's scripted to some amount and then something unexpected happens and it's an adventure where the viewer knows about as much as Linus and the writer do about what's going to happen
Tbh, LTT videos are just scripted on the planning side. Like they make a script sometimes but actually they are like not straight up following it. They have their honest reaction and stuff, while things are just made sure it will be entertaining and accurate. Honest reviews, tests, and a lot of out of camera work which includes making sure the quality and accuracy of the video, while also the research, lab testing, and experiencing in the background(like Linus said in this video, that the test were show different outcomes, then they accidentally pulled an AMD system and the whole theory was faked and noone knew why suddenly)
@@kodi0223 well, I think what they might have had issues with in Windows is every time you plugged something in it would start to load extra drivers, which itself causes a big spike in CPU usage, etc. Linux doesn't do this.
I’m not sure if it’s part of Labs but it would be cool to see how much power each peripheral draws. In this video it would be interesting to see how much power was flowing to the hub from the motherboard.
As someone with questionably too many peripherals, I experienced problems with connections and disconnections constantly, first I thought it was a PSU problem, but further diving found it was more of the bus/controller. StarTech makes a PCIE card that comes with 4 usb slots each with their own individual controllers and I've not dealt with any issues since buying. Love seeing it being validated like this.
Funny enough, I ran this experiment a number of years ago (2005 ish) running under Windows XP. Ultimately, I was able to get 212 devices (plus 20+ hubs) connected to a single Dell laptop. For the "127" device limit, I found that that was 127 devices per host controller. Most PCs have a couple of host controllers - this Dell with a docking station had 3 or 4. The other thing I found was that each device plugged in seemed to take about .5 percent of the CPU ... I suppose to maintain communication with it or some type of overhead with the driver. After I had around 200 devices online this .5 percent had finally added up to nearly 100% CPU utilization just sitting there. As I turned on the last 12 devices, the friendly "ding dong" sound Windows makes when a new USB device comes online slowed waaaay down. Device 212 literally had a 15 second long diiiiiiiing-doooooong sound. 213 never registered being powered up. I think the hardware could have theoretically handled more devices, but the CPU was maxed out. This was all for an actual legitimate purpose. I wasn't using thumb drives and it took some creative mix of powered and unpowered hubs to be able to power all the devices themselves... but, way past the "127" mark.
I want to know the software limit for 95, 98, 2000, XP, 7, 8 and10. There must be a software limit. usb emulator software should be able to easily find it.
@@spike5499 haha - i was working for a science company and some researchers wanted to build a cheap lysimeter network (in this case, a lot of scales plugged into a PC.) 212 was the max number of scales I got (sorta) working on the laptop. It was stable and very usable with about 60-80 devices connected. Learned lots of tricks and hacks of USB to get it all working. 1 well powered (4+Ah) 7 port hub that could power a 4 port unpowered hub on each of its 7 and then a scale in the 28 available ports. A "branch" like that X4 will get you a little over 100 devices. For the 212 push, I had to use every port on the laptop plus docking station; including cutting a hole in the dock so I could still use the rear USBs that were normally replicated (but blocked) by the dock itself. I found that to keep it all stable, it worked best forcing all the USB to v1.0/1.1 ... disable 2.0 capabilities. It was much more forgiving to the number of hubs and long cable lengths this way.
I work on a computer that actually uses 128 (plus 16 hubs) USB 2.0 devices plugged into a single Linux machine. We really did use 128 USB thumb drives to test it out before assembling the full mess. It got quite a bit harder when USB 2.0 root hubs stopped becoming easily available. USB makes a great sideband protocol for bootloading and management.
@@kingmaxlol64 I'm going to guess automation. I've dealt with pharmacy automation systems that use USB for communications have ran over 80 devices on a single system but never that many. I notice crappy controllers get flakey at around 50 or devices but solid controllers handled the 80 no problem (HPe workstations).
FYI: A USB device will have a different ID when moved between ports - say like a serial adaptor moved from USB 1 to USB 2 would go from COM1 to COM2. Keep this in mind when using a USB device - Windows will remember each device plugged in, and which port it was on. Prepping USB devices for shipment can fill the registry with crap that's old, etc. Great video BTW. You are "The EXTREME!"
It's annoying, but helpful that it does this. One time I had a device malfunction on one port, yet it was fine on another. It stayed broken on that one port too.
@@sannjogsos3009 The 127 endpoint limitation is currently built into USB because of the addressing. The USB addressing scheme is limited to 7 bits. No matter what system the controller is running on, each root controller can only address 127 endpoints to communicate to.
I remember reading some real old computer industry magazine in which they were talking about the release of Windows 95 OSR2 and the new USB 1.0 standard so a few industry people wanted to test USB 1.0's 127-device connection limit. The article says they had a bit of trouble finding 127 unique devices but eventually they did and they all worked when connected
Finally… I need more info on this. Flight sim IO is acting weird.. I have researched USB tiers and PCIE lanes vs onboard chipsets/controllers and it’s just nuts
This is actually relevant to me since my flight sim setup uses multiple Arduino boards as well as other USB devices. I currently have 6x Arduino Mega, 2x Nano, Logitech rudder pedals, Honeycomb Yoke/Throttles, Wireless headset, Keyboard, Mouse. Sure I have 2 powered USB hubs, but considering I still have more planned upgrades knowing the USB limits is useful.
@@SupremeLordGeek So far so good but I'm planning on at least 2 more Mega boards. Running a 5800x 3d so I'm hoping Zen 4 does me well with USB support lol. I have 2x Sabrent powered USB hubs similar to what they used.
Great video and really cool to find out more about how controllers distribute bandwidth and power. The amount of USB ports on modern motherboards is insane, back in the day I remember having plenty of add in cards.
Linus, question: Is it possible that some of the keyboards that you used could also act as a hub and have a USB port on it increasing the amount of devices connected? Just a thought experiment.
@@Hbk1998GIf the keyboard is USB and it offers a USB port on it, it has to have an internal hub, else its own use as the keyboard would be all it could do.
@@Simon-tr9hvIts not a pass through, its a hub, hubs are everywhere, including splitting the ports on the motherboard, its why multiple controller usb cards cost a decent amount more than the dubious ones.
"Unbelievable. I can't believe they just allow more power draw so things function properly. *sigh*"... Tanner's dry sarcasm is such an absolute treat in these videos.
I'm so glad there's somebody like Linus around. This is exactly the same sort of stuff I thought would have been doing when I was younger but couldn't afford. Now that I'm older and still curious and could afford I don't need to because of your shenanigans!
@@morbus5726 brother if you think capitalism woes sway me youre barking up the wrong tree. We love in a society that allows exploitation, wanna cry about it? Fix it
@@ferybrand1990 what? I'm just pointing out that he does some horrible things, countering your point that hes a "Bob Ross" or "Mr. Rodgers" type of guy. I'm not sure how you want me to fix it??
It's also worth noting that some "active" USB extension cables (typically cables over 5 metres) actually use a hub chip, they're effectively a single-port hub according to the system. I think other kinds of usb "boosters" may exist, but presumably as hub chips are cheap that seems to be how active extension cables usually come.
From what I understand an active USB cable can be made with a very simple logic buffer circuit that adds pretty much no latency to the system. I suspect cables using hub chips is either reusing defective hub chips (eg only one downstream port works) or companies that already have tons of hub chips on hand for making hubs to the point that it's cheaper to use those than it is to also stock buffer chips.
I loved the video for being so educational as many pointed out, and I also love Tanner's energy. Props to this man for the joke at 22:48. Although depression is not a joke, but an illness, being able to chuckle about it is what makes your life a bit brighter. Thank you, Tanner, this one made my evening.
One of the best videos you've made. Theoretically understood all of the limitations, but to actually physically test this just looks like amazing fun! And the AMD tests are just damn bizarre and awesome!
i don't think its an extremely powerful USB host i think its just more bugged than tanking because none of those actually worked AMD is still very buggy for no reason
@@kieranlee9610 its more that the y will let you pile it on until you crash. It gives you a little bit beyond the official standard, whilst simultaneously becoming exponentially more buggy the further beyond the standard you go.
personally, i just love the look on Linus face 2 minutes in when he's like "Wait this mouse is hot?" The look and voice that screams "i was expecting to possibly break something today, but not this quick and why in the HECK would it be the MOUSE of all things?" Sher he Holcked it out quickly, but the momentary confusion just gets me.
The limit is not the number of devices but the number of endpoints per hub controller. With newer USB 3 you could connect up to 4096 endpoints. Intel xhce controllers are famous for not complying with that limit, furthermore different versions of the chip have different limits ranging from 64 to 192. AMD supports a lot more of endpoints.
If intel figures out a way of saving some money so one of their theoretical limits is lower but they don't think anybody in the real world will complain about it, they will do it.
Along the same lines of this video, I would love to see the team investigate the USB 3.0 interference with 2.4GHZ devices (such as wireless USB dongle mice, & bluetooth even).
This is absolutely insane, and I love it! I don't have enough USB ports on my system so I've always been interested in getting a powered hub and that 16 port looks awfully interesting now.
This video is very relevant to my work. I got 20 port powered hubs that take 2 usb B 3.0 inputs. (basically two 10 ports hubs in one unit) I flash 40 galaxy phones at a time and it takes forever because of the bandwidth, pushing 7.5 GB to 40 devices. I have 3 usb PCI cards so basically 10 ports per controller. I would love to flash more at a time but wasn't sure where my bottleneck is
I remember back in the days before USB, we used serial ports, and a PC would likely have one or two, and the most I saw on one system, with a controller that cost more than my gaming PC at the time, had 8. The resources used by each port pretty much limited it to 8 ports per system. Having so many devices today is such a luxury.
I worked at a place in the late 90:ies where we had loads of more serial ports than that on a single pc, the trick is having the kind of cards that offloaded some of the processing to the card itself. It was used to run a modem pool, but I think that I remember it being the same number as you, aka 8 per card.
Yeah, I remember reading one of dad's old "how computers work" books, and it talked about SCSI daisy-chaining (the predecessor to doing the exact same with USB)... Apparently, you could make some real crazy stuff happen back in the day if you had enough devices, enough cables and ports, and zero fscks given.
I found this out a few years ago! Depends on the system! Also, some Unraid systems wont boot if you have so many USB drives in that it pushes the bootable USB off the boot device list.
Lol, that sounds like a fun headache. I recently changed motherboards and there are physical slots for 8drives but the silicone only supports 6, so when you turn it on it would randomly select 2 drives and not detect them. I figured it out quickly enough, but didn't notice this at time of purchase and needed to buy a raid card.
@@CyberbrainPC It was clearly written in the spec so i have only myself to blame..... though a better eufi diagnostic message would certainly be a welcome improvement. I tried switching cables before checking spec, so i guess it'd have saved me 10mins.
6:44 Okay but drop the motherboard info. Need one that'll work with what it's given. I'm not dainty with my stuff so I get extra-reliable, extra-durable versions whenever possible.
10:30 It seems like you guys forgot about the USB-BC (battery charging) spec which allows basically any USB-A port to pull a much larger current than the USB 2.0 and 3.0 specs originally allowed. In some cases, up to 2.4A for a total of 12W. This is why USB-A charging stations often have 2.4A ports. The USB-A plug is supposed to be able to handle 3A without catching fire to remain in spec. Whether or not the host controller allows that much is another thing.
@@Cyberguy42 The Huawei P20 Pro and P30 series were shipped with an official Huawei fast charger with a 5V 5A port, and a corresponding "5A" USB A to C cable. The Oneplus 3, 5 and 6 had a 5V 4A charger, for example
Linus - Genuine idea for a video. Do a USB hub rundown of cheap or unbranded hubs compared to good ones. I recently bought a hub marked as USB 3.0 and when a USB 3.0 device was plugged into a USB 3.1 port via this hub it slowed the data transfer down to USB 1.1 .... It was clearly a con, but there are thousands of sellers trying to flog them with dodgy misleading descriptions on eBay and Amazon (who don't care). Call the scam products out and do a wonderful consumer awareness video all in one 👍
To be honest powered cheap USB hubs kind of scare me. I've seen some actually send voltage down from the hub into the motherboard. You got to even watch out for some USB devices having malicious firmware which may have keyloggers on them. I just buy directly from trusted manufacturers for things like USB devices, SD cards, etc. Found that out after getting scammed with a fake Samsung micro SD card which looked legitimate until I started running some tests.
Another challenge connecting 100+ input devices is it'll only take one with one stuck button or key to cause issues, let alone all the razer-like devices auto-installing software next to their drivers it's still mindblowing you managed to get so far!
@@jswclips8459yeah, he stepped back and let his former boss take his place, so he can completely focus on content creation again, without the whole headache that comes with being the CEO of a multi million dollar company
@@jswclips8459 Nah he hired someone else as CEO so he can do the stuff he really likes in the company. He's like, Chief Vision Officer or something like that now?
Brilliant video, one of the best for a while! This is the type of content that makes me excited to learn more about computers, like yeah, how does the USB spec actually work?! Props to the writer he did an excellent job and he's a great on-camera personality too!
I love the fact that the video turned into "Let's see how many devices we can plug in until it stops working" to "HOLY CRAP WE'RE SO MUCH PAST THE LIMIT AMD WHAT THE HECK"
For USB storage devices : In windows you also have the drive letter limit, so you cannot add more than upto drive Z (I think there was a hack to be able to also use drive letters A and B which are for floppy disk drives). In linux though there is a possibility that it might work.
This is true only for drive letter assignments, windows allows attaching disks to empty folders just like Linux does, and can address a nearly infinite number of volumes this way.
@@regrettspaghettt No - Linux wraps around at sdz to sdaa, sdab etc, and then will move on to sdba after that until you reach sdzz at which point it will go to sdaaa and so on.
In windows you can mount drives to folders Unix style, using disk manager. In disk manager, right click on the drive, select "change drive letter and paths" remove the drive letter(optional) and in "add" you will see an option for "mount in the following empty NTFS folder"
With all the new lab equipment I'd love to see a test of lots of different dashcams, see if the expensive ones are worth it 🤔 *edit: didn't realise they've already done one, maybe a more in depth one or possibly diy jank one 👀
they have already done a video on dash cams, and their result was pretty much none of them are, i would like to see a more indepth one tho, as someone who is looking to get their first car soon i definitely intend on getting one
I'm a bit late, but it could be because some people may have really cold hands. For example, going outside in winter, standing in front of a fan, or having a cold snack.
When I saw the start of this video I was expecting weirdness with keyboards being more than one device per keyboard. I was not expecting you to not think of it "live" in the process. Early on I learned in device manager keyboards do this for n-key rollover while messing with a keyboard that had 6 key and n key rollover (would switch from being 3 and 6 devices in software). It was very fun to watch the issues occur in real time.
It would be interesting how a different kernel (like Linux, Linux ZEN, Linux mainstream, Proxmox, Unraid, etc.) would handle it. It would also help Server owners that work with virtual computers and real I/O hardware (GPU and USB passthrough).
This was filmed the Thursday before LTX. The janky mess of keyboards and usb hubs was in the floatplane tour video. I'm guessing Linus is taking some time out to recover from the LTX madness.
Just to ellaborate more on the limits: The upper limit for devices in a single USB network is, per the USB specification, not xHCI, 127, as correctly stated (128 from 7-bit address length, but address 0 is reserved for any un-enumerated device so the host can talk to them and enumerate). xHCI for some reason allows up to 255 devices (8 bit address) but I can make no sense of how it would actually work, because USB simply can't handle more than 127 because of the address size, maybe 2 separate networks in a single controller, each on a separate port, but I've never seen it. Each device can have up to 31 endpoints, also per USB specification, not xHCI (that's 16 from 4-bit endpoint address, but each endpoint address except for 0 can have one IN and one OUT endpoint. Endpoint 0 is special because it's a single IN/OUT endpoint exclusive for the control channel). So the absolute upper bound (for a single controller) is 3,938 IF you consider 0IN and 0OUT as a single endpoint (device 0 always has the 0 address endpoint). No controller I know of actually reaches anywhere close to this, so you can have anywhere from 96 (for Intel chips AFAIK) or even lower for embedded MCUs for example, but there's no reason to stop at 128 really. The reason host controllers have endpoint limits but not really device limits (lower than USB capabilities of course) is because each endpoint usually requires a dedicated FIFO queue in RAM to handle communications, whereas a device is just an address number. Also in some controllers endpoint 0 is implemented as two separate endpoints because it makes more sense as it needs both IN and OUT capabilities so the actual endpoint limit may be lower than it seems
Id love to see you guys do a followup showing what kind of damage could be caused by overdraw on USB ports (not so much fire, but degeneration of motherboard parts/ports/etc. How does this effect the longevity of the devices being used, etc.
I once saw a computer with 120 USB ports at a hardware exhibition in China, and I'm not sure that so many ports could work at the same time. This machine was designed to be used to manage a fairly large number of USB hardware keys for social insurance accounts at the same time.
Another reason why an unpowered hub might want to allow hubs to be connected to it is because some keyboards are actually hubs. As in your keyboard will be a keyboard connected to a hub connected to your computer (where the keyboard has other usb devices or ports on it)
I’ve had issues with plugging in too many hubs rather than too many devices which is interesting. Having the same amount of devices plugged into two hubs seems to work better than having them plugged into 4 different hubs. Also some hubs work almost flawlessly whereas others just keep dropping out when I connect thumb drives to them but peripherals work fine… USB stability, even more than the instantaneous number of devices you can have plugged in, is a big issue and it would be worthwhile to investigate stability in a seperate video. I will say that having a seperate usb controller via pcie definitely improves stability! I’ve noticed that. But when I plug in multiple external hard drives I have significant problems with them just disconnecting intermittently even if they are on seperate controllers (this happens more often under high bandwidth usage but also seems to happen even if I’m just using the drive a little bit??). I’ve noticed this issue on different devices; my old Dell intel 7th gen i7 laptop and on my X99 5820k PC. 4 port powered hubs seem more stable than 7 port powered hubs and 7 is more stable than 13 port hubs; but I have another specific 8 port hub that isn’t sold anymore and for some reason is super stable. Maybe stability varies on vendor or newness of technology like Linus noticed on AMD vs Intel. I wonder if there’s a measurable difference on USB stability and % uptime on Windows vs Mac or from vendor to vendor
There's definitely a difference between the chips in different brands of hubs. We used to run in the same issue doing backups to multiple external drives and we didn't try and copy something to all the external drives at the sane time but rather one after the other and we figured out that some powered hubs just are better than others and actually motherboards as well. We eventually also fixed it with a board with a bunch of PCIe slots and USB cards as opposed to USB hubs. Laptops on the other hand are all over the show and some laptops (modern and old) just really don't like having a bunch of USB devices at the same time.
That motherboard probably has a different host controller for each of those USB ports they are using. Some better motherboards give you one host controller per bank of ports, other motherboards give you just one host controller for all the USB ports.
![[RANT] The DUMBEST Thing About USB](/img/n.gif)
This actually makes me appreciate the USB standard. Not only the fact you can just plug anything into it and expect it to work 99,9% of the time without any additional input, but also the fact that everyone just agreed that this is something we're going to be using on just about everything.
When they called it "universal" they really were onto something.
But in the early days, USB was called *Plug and Pray* because it barely worked for anything but keyboards and mice.
@@BritishBeachcomber It was a godsend for printers, especially in a house where you didn't need to have the printer plugged in all the time. I don't miss parallel ports at all. And most keyboards and mouses were still PS/2 in the earlier days, at least around 1999/2000. I feel like you had to go out of your way to find a USB keyboard or mouse, and there wasn't much point to doing so, since nearly all mobos still had the two necessary PS/2 ports.
@@billyeveryteen7328 yea parallel ports are something alright. I have barely used it ever outside of VM, and emulation purposes.
It's still annoying to use even in that scenario.
There may be one or two extra 9's in there... but it's impressive nonetheless!
These limit finding videos are great for understanding our pcs more without having to go out and figure it out every single time.
Yeah, this was just a framing device for Linus to teach us about how the usb standard actually works
What is the limit of can(controlled area network) buses to usb adapter limit for modern computers?
well no shit
stackexchange is for this too.
Legit this is stuff you would cover in computer engineering classes.
Linus and his team doing something completely unreasonable but still somewhat educational is my favourite type of content
I subscribe exclusively for the completely unreasonable but somewhat educational content
*Clickfarm enters the chat*
Not unreasonable. If I buy cheap Chinese 1time USB sticks, I need to check every stick for forgery with f3 - fight Flash Fraud. With Linux I use 12 port hubs and 50 sticks a limit. Depending on the PC I cannot use that many. With an i3 the USB3 windows device limit was 8!
With a XEON 50 worked slowly.
With my 4600h 50 no issue
This and the janky stuff, especially related to cooling
This actually helped me out with figuring out how to deal with my valve index and many other USB devices fighting over USB resources lol
My favorite thing is when the system just starts kicking devices off. It's like the computer's hosting a house party and way too many people start showing up, until the host just loses their shit and starts throwing people out. "I said you could bring a plus one, not a plus thirty-one, get out!"
For those who don't know, USB Tree View is the OP GOAT program for this stuff. It shows you all connected devices and their level so that you can diagnose issues. If you've ever had the annoying reconnecting USB device that keeps chirping its connection sound on and off, this is the tool to use. It'll highlight funky devices just as it did in this video.
lsusb enters the chat
@@Codeaholic1sus
Oh, thank you! I was wondering what software they were using!
@@foofoodogWait, this isn't NetPositive!
@@Codeaholic1lsusb -v
(22:46)
Linus - "Oh, crap, something is depressed."
Tanner - "Uh, sorry."
Gotta love Tanner
As a USB4 System Validation Engineer at Intel I found this video super interesting ,entertaining and educational.
Great job Linus 👏
@@sophiophiletheory and reality. If you don’t know that’s there’s a huge difference you are not working in development, no matter what…
@@sophiophile Spec is one thing, reality is another.
@@sophiophile Google what a validation engineer does, different than verification, emulation & testing. So there's 4 different job roles to ensure something is working.
The bad news is now... You will be plugging in a lot of USB devices at work from here on out to solve and fix issues as the limits must go up! :D
can you please share some knowledge you have gained over the years working on usb. like troubleshooting and stuff..
Every so often I get re-amazed by USB. I started using computers near the end of the 80s on a DOS machine and the hot-swappable, plug and play nature of USB really changed the game.
And the fact that almost every device uses the same connector is so damn useful.
@@lukethmpsn For real. I still remember days when you bought new phone and almost every one of them had different power supply plug, you could buy those junky power supplies with full palette of plugs that usually broke after couple uses. Those were the times
Not only data but power too. Not too long ago every small low voltage/amperage device used a little barrel jack connector or some proprietary thing for cell phones. If you were lucky you'd be able to find that one wall wart from some device you may or may not have had years ago. And even if you found one that matched the voltage and jack size you'd still have to squint and see if the jack polarity was correct. All small battery chargers used to require a wall outlet and low voltage hobby stuff like small wind/solar was a hassle because everybody did it a different way so wrangling your charge controllers was much more of a pain.
Now it's all 5v over USB. If it's small and cheap it'll probably take USB. Even if USB charges slower than some of the older methods because of massively improved modern lithium batteries you'll still probably be charging it less.
Things are so much easier now.
@@axelxanI still have boxes full of Nokia cables that came with the unlocking box 😅 It wasn't the only one making a different cable for each but man, it was the most
ya when usb first came i laughed... i was like ya thats gonna work
i stopped working in traditional IT departments way before it was "cool" this channel is a gem for old timey IT guys who miss the crazy IT department shenanigans we would do in the server room on off days. thanks for these!
If anyone is looking for the software Linus is using to list the devices plugged in, its called "USB Device Tree Viewer". Made by some german person called Uwe Sieber :)
thank you
Savior
This should be the most upvoted comment! 🤣
Thank you!
Thank you
Linus did a good job explaining the different limitations imposed by the USB spec, but there is one more he didn't talk about: time. More specifically, scheduling of the USB request blocks inside a USB frame that's sent out, at most, once every millisecond (in the case of USB 2.0 at least, don't know if they raised it in later versions, but I don't think so).
He mentioned the four types of endpoints: ones for configuration (Control), rapid but short message transfer (Interrupt), large data (Bulk) and continuous transfer (Isochronous). What he didn't talk about is that you can't just mix'n'match them willy-nilly, because there's a limit of how much of the frame each of these types of endpoints IN TOTAL are allowed to occupy. For instance, IIRC the limit for Interrupt types is 10%. This endpoint type is used by keyboards, mice, game controllers etc., so if you only have these devices in your system, you will effectively only be able to use at most 10% of the full bandwidth of USB.
I don’t know what’s more impressive, the fact it (almost) handled 127 USB devices, or the fact they were able to find 127 devices around the office that hadn’t already been stolen (as we’ve seen is a common theme from $5000 tech upgrade videos.)
It was a bring your keyboard and mouse to work day. With the amount of staff LTT has now, they had more than enough.
The real question is how many USB devices can Linus drop at once?
Agreed
Yes
Take the answer from this video and add 12.
More than 4 at any given time.
All of them
Imagine how many times Linus had to turn USB connectors to get them to actually plug in. Truly a dedicated man.
3 sides minimum per drive, must have taken a while...
There is a trick, on each side of the usb stick are 2 squares. If they are filled with plastic or something it’s the bottom side, if they are empty its the top side
@@arriswaasdorp4111that trick usually gets me from 5 attempts to just 3
he got the ones that dont have a switch and give power either way
Its Atleast 3 per plug. I've never done it in less..... It takes me 2 tries for usb c.
I think the fact that you could plug in more than 128 devices is a relatively recent thing potentially starting at the 3000 series CPUs. I was running into USB issues on first gen Ryzen and I wasn't anywhere close to those numbers and I was having many of my peripherals turn off and then turn back on like they were reset on the addressing end. I added an internal USB controller card and that completely solved my issue.
And that’s like…. One of the things they actually fixed lol. I couldn’t imagine having a USB device not working because of the parts I have. At least when USB was introduced, stuff still worked and they most likely shipped with a floppy disc for the driver
@@Thewaterspirit57 Damn USB is old. Physical media is so pointless and such a waste of resources.
@@roots4x Dude no. Physical media exists to preserve things. If companies stopped making physical media including drivers, then there would be most lost media and also more older hardware thats useless cuz the driver was never archived or was deleted.
@@Thewaterspirit57 it’s almost assuredly easier to find drivers online or from your personal archives than from a floppy disk somewhere. You can easily dedicate a$5 USB drive to driver storage, or have a backup for another $5. It’s a huge waste of resources to ship a floppy drive to every customer in the age of the internet.
@@roots4x Bro, those cloud servers likely use USB ports one way or another. Just because we dont see the Cloud doesnt mean its not somebody else's physical media or computer
In the unix/linux world, handling interrupts for low speed i/o is a huge PITA. A bunch of USBs sounds like a great stress test.
I guess that kinda answers my question if linux would far better or not given server & supercomputer usage
@@arnabbiswasalsodeep today's small systems have more oomph than the big systems from when Unix was created. The big difference was I/o channels. You don't need those now thanks to things like iscsi, but back in the day, you had to attach it to the system, e.g. DASD on block mux connectors for disks and tape drives.
@@arnabbiswasalsodeepit is
@@arnabbiswasalsodeepit probably would be better for some stuff storage comes to mind where the lettering of drives in my experience isn’t a thing.
@@U1TR4F0RCEBlock devices under Linux are still lettered (sda, sdb, ...) but when more then 26 a present another letter gets added (sdx, sdy, sdz, sdaa)
I love how it just turned into a Techquickie episode half way through, even thought they had gone onto a green screen until Linus grabbed a hub from the table lol
Yes, why wasn't this a Techquickie episode?
@@DizzyBusybecause it's not very quick
Some powered hubs also had this rather dangerous flaw in that it connects directly to the VBUS pin to the host, so it can backfeed the power to the computer, which can damages the controller and sometimes the entire computer if it was a laptops or all in ones. BigClive has a video about this that explains it pretty well.
I had one of those, it was trippy. Wasn't a big deal if the USB ports remained active when the system was off. Unplugged though, that was whack and I did not like that thing because of it. It was one of those "optionally powered" hubs though, and I'm sure those are the main ones that are notorious for it, which is sad cus a couple of diodes are all that would be needed to prevent the backfeed.
Just have usb certified and high quality hub and it shouldn't be a problem
BigClive did mentioned that many cheap USB charger tester with a socket can be “backfed” and it would light up, I have a couple that also have the same behavior, so that’s a good way for quickly test a USB hub for backfeeding flaw, so far I found 2 hubs that have the backfeeding problem.
@@pojcharapoltosukowong I would imagine that those hubs can be used powered or non-powered...
Wow, imagine being so stingy that you wont put a simple $0.02 diode to protect the PC.
(technically 1N5399G costs $0.012 when bought in bulk, so even cheaper than $0.02).
Please do more videos like these in the future. I love the idea of exploring the theoretical limits of different PC components.
If I'm not mistaken the CPU polls each device many times a second as well, so that's a good amount of CPU overhead. I wouldn't be surprised if there's significant delay between pollings and some devices not liking that.
All those gaming things demanding polling at unreasonable speeds
@@ptamogyeah >1kHz peripherals don't make any sense unless you're actually a pro and you've got a 360Hz+ monitor, consistent fps higher than the refresh rate, and optimized all the low hanging software settings. even going from 1kHz to 8kHz that's shaving only 0.875ms off input lag...
I believe the actual polling is done by the USB Host Controller, not the System CPU. When there is a result from the poll, when say a key is pressed or mouse movement occurs and so on, there could be CPU overhead servicing that, though.
@GeekProdigyGuy they make plenty of sense. The higher the peripheral refresh rate, the more consistency between each individual mouse movement.
They matter mostly for quick precise actions such as gaming.
And if the polling can't happen in time the device probably times out and resets the connection. Which will make the situation worse lol
USB does a lot of polling, so when there is a ton of devices, each gets a chance to speak, which slows things down. Even if they are low load devices. You also may need to wait for everything to handshake and initialize after you connect them for a WHILE, then see better stuff working.
I love how unscripted this episode is, and I do mean this 10/10. Please do more vids like this!
The heated mouse got me.
It was scripted but then the writer happened to grab an AMD machine which reacted completely differently to this experiment than the Intel machine he did all his testing on. Most ltt videos are basically scripted down to the word. Some are partially scripted and partially off the cuff and then there's ones like this where it's scripted to some amount and then something unexpected happens and it's an adventure where the viewer knows about as much as Linus and the writer do about what's going to happen
Tbh, LTT videos are just scripted on the planning side. Like they make a script sometimes but actually they are like not straight up following it. They have their honest reaction and stuff, while things are just made sure it will be entertaining and accurate. Honest reviews, tests, and a lot of out of camera work which includes making sure the quality and accuracy of the video, while also the research, lab testing, and experiencing in the background(like Linus said in this video, that the test were show different outcomes, then they accidentally pulled an AMD system and the whole theory was faked and noone knew why suddenly)
Would love to have seen how Linux would have handled it. Would have been a good test to determine if it was a driver issue or not.
Linux gang gang gang
I doubt that Linux would have any issues with that amount of devices.
I would be interested too. At the very least it would probably need less CPU
I can just imagine a: watch 'lsusb | grep -v hub | wc -l' command running...
@@kodi0223 well, I think what they might have had issues with in Windows is every time you plugged something in it would start to load extra drivers, which itself causes a big spike in CPU usage, etc. Linux doesn't do this.
I’m not sure if it’s part of Labs but it would be cool to see how much power each peripheral draws. In this video it would be interesting to see how much power was flowing to the hub from the motherboard.
When they were trying to figure out why everything was still working at the beginning I really wanted them to check the actual power draw.
There are 5$ USB passthrough devices that can do this, I use them to test cables as cables don't tell you what protocol they can run
I have a suspicion the one hub with the USB's may have been overheating and the chips crashing
@@tonnentonie2767 LTT has those as well as fancier ones, they just didn't pull them out
14:08 "Wooooooo !! Let's go !! New world record !!" 😂
As someone with questionably too many peripherals, I experienced problems with connections and disconnections constantly, first I thought it was a PSU problem, but further diving found it was more of the bus/controller. StarTech makes a PCIE card that comes with 4 usb slots each with their own individual controllers and I've not dealt with any issues since buying. Love seeing it being validated like this.
Funny enough, I ran this experiment a number of years ago (2005 ish) running under Windows XP. Ultimately, I was able to get 212 devices (plus 20+ hubs) connected to a single Dell laptop. For the "127" device limit, I found that that was 127 devices per host controller. Most PCs have a couple of host controllers - this Dell with a docking station had 3 or 4. The other thing I found was that each device plugged in seemed to take about .5 percent of the CPU ... I suppose to maintain communication with it or some type of overhead with the driver. After I had around 200 devices online this .5 percent had finally added up to nearly 100% CPU utilization just sitting there. As I turned on the last 12 devices, the friendly "ding dong" sound Windows makes when a new USB device comes online slowed waaaay down. Device 212 literally had a 15 second long diiiiiiiing-doooooong sound. 213 never registered being powered up. I think the hardware could have theoretically handled more devices, but the CPU was maxed out. This was all for an actual legitimate purpose. I wasn't using thumb drives and it took some creative mix of powered and unpowered hubs to be able to power all the devices themselves... but, way past the "127" mark.
I want to know the software limit for 95, 98, 2000, XP, 7, 8 and10. There must be a software limit. usb emulator software should be able to easily find it.
how and why did you get 212 devices 😭
@@spike5499 haha - i was working for a science company and some researchers wanted to build a cheap lysimeter network (in this case, a lot of scales plugged into a PC.) 212 was the max number of scales I got (sorta) working on the laptop. It was stable and very usable with about 60-80 devices connected. Learned lots of tricks and hacks of USB to get it all working. 1 well powered (4+Ah) 7 port hub that could power a 4 port unpowered hub on each of its 7 and then a scale in the 28 available ports. A "branch" like that X4 will get you a little over 100 devices. For the 212 push, I had to use every port on the laptop plus docking station; including cutting a hole in the dock so I could still use the rear USBs that were normally replicated (but blocked) by the dock itself. I found that to keep it all stable, it worked best forcing all the USB to v1.0/1.1 ... disable 2.0 capabilities. It was much more forgiving to the number of hubs and long cable lengths this way.
WHAT
I work on a computer that actually uses 128 (plus 16 hubs) USB 2.0 devices plugged into a single Linux machine. We really did use 128 USB thumb drives to test it out before assembling the full mess. It got quite a bit harder when USB 2.0 root hubs stopped becoming easily available. USB makes a great sideband protocol for bootloading and management.
For what scenario do you need that many devices?
@@kingmaxlol64 I'm going to guess automation. I've dealt with pharmacy automation systems that use USB for communications have ran over 80 devices on a single system but never that many. I notice crappy controllers get flakey at around 50 or devices but solid controllers handled the 80 no problem (HPe workstations).
@@kingmaxlol64 I will guess Phone Farming? Unfortunately they are common in certain places.
Very informative.
Love that with Linus not knowing it was a heated mouse. 😁
For what it's worth, the videos where things go off the rails are always my favorite.
FYI: A USB device will have a different ID when moved between ports - say like a serial adaptor moved from USB 1 to USB 2 would go from COM1 to COM2. Keep this in mind when using a USB device - Windows will remember each device plugged in, and which port it was on. Prepping USB devices for shipment can fill the registry with crap that's old, etc. Great video BTW. You are "The EXTREME!"
It's annoying, but helpful that it does this. One time I had a device malfunction on one port, yet it was fine on another. It stayed broken on that one port too.
@@ArtisChronicles It was helpful that it stayed broken?
The answer: yes.
What's the difference between chicken tenders and chicken strips? Their both strips of chicken? So why different names?
@@StewieGriffin1901yes
@@My_cat_is_so_cute agreed
agreed x2
0:31 he just plugs in a usb stick and gets it on the first try. Looks fake.
Would've been interesting to see if behaviour was much different in linux, since it seemed to become a driver limitation at the end.
They would have needed wendell to know whats going on in the linux kernel
Does mac also have that limitations?
Since they use thunderbolt, will speed or any other component be affected when that many devices are connected?
@@sannjogsos3009 The 127 endpoint limitation is currently built into USB because of the addressing. The USB addressing scheme is limited to 7 bits. No matter what system the controller is running on, each root controller can only address 127 endpoints to communicate to.
I remember reading some real old computer industry magazine in which they were talking about the release of Windows 95 OSR2 and the new USB 1.0 standard so a few industry people wanted to test USB 1.0's 127-device connection limit. The article says they had a bit of trouble finding 127 unique devices but eventually they did and they all worked when connected
Finally… I need more info on this. Flight sim IO is acting weird.. I have researched USB tiers and PCIE lanes vs onboard chipsets/controllers and it’s just nuts
I can confirm this absolutely with VR equipment, but also better stability with flight sim gear.
Mythbuster moment for ltt
Valve index dongles are weird too
@theflightwrightsgaming906 I assume they mean IO == input output so all the controls like switches and throttles
@@lemonoxygen8846 lemon is correct. I was referencing the amount of available input/output devices
Video Idea: Have the whole office try to win a game with this setup
This is actually relevant to me since my flight sim setup uses multiple Arduino boards as well as other USB devices. I currently have 6x Arduino Mega, 2x Nano, Logitech rudder pedals, Honeycomb Yoke/Throttles, Wireless headset, Keyboard, Mouse. Sure I have 2 powered USB hubs, but considering I still have more planned upgrades knowing the USB limits is useful.
Buying a PCIE USB card will probably allow more devices if you need it
@@SupremeLordGeekthis
Yeah, before I got into flight sim I would've just shrugged this off and said "but who cares", lol
@@SupremeLordGeek So far so good but I'm planning on at least 2 more Mega boards. Running a 5800x 3d so I'm hoping Zen 4 does me well with USB support lol. I have 2x Sabrent powered USB hubs similar to what they used.
Great video and really cool to find out more about how controllers distribute bandwidth and power. The amount of USB ports on modern motherboards is insane, back in the day I remember having plenty of add in cards.
Linus, question: Is it possible that some of the keyboards that you used could also act as a hub and have a USB port on it increasing the amount of devices connected? Just a thought experiment.
Most keyboards I know have only one usb port which acts like an extensions for another port on your pc.
@@Hbk1998Gno there are many that actually are usb hubs. Take the old apple keyboard as an example
there is one for the Raspberry Pi with two of them.
@@Hbk1998GIf the keyboard is USB and it offers a USB port on it, it has to have an internal hub, else its own use as the keyboard would be all it could do.
@@Simon-tr9hvIts not a pass through, its a hub, hubs are everywhere, including splitting the ports on the motherboard, its why multiple controller usb cards cost a decent amount more than the dubious ones.
"Unbelievable. I can't believe they just allow more power draw so things function properly. *sigh*"... Tanner's dry sarcasm is such an absolute treat in these videos.
“Something is depressed”
“Sorry”
Had me WHEEZING
I'm so glad there's somebody like Linus around. This is exactly the same sort of stuff I thought would have been doing when I was younger but couldn't afford. Now that I'm older and still curious and could afford I don't need to because of your shenanigans!
He really is like a Bob Ross or Mr. Rodgers for our little corner of the internet.
@@ferybrand1990 with a little but of Bill Nye mixed in.
@@ferybrand1990 to bad he screws over tiny companies like billet labs, auctions their parts without consent, and refuses to admit his mistakes.
@@morbus5726 brother if you think capitalism woes sway me youre barking up the wrong tree. We love in a society that allows exploitation, wanna cry about it? Fix it
@@ferybrand1990 what? I'm just pointing out that he does some horrible things, countering your point that hes a "Bob Ross" or "Mr. Rodgers" type of guy.
I'm not sure how you want me to fix it??
It's also worth noting that some "active" USB extension cables (typically cables over 5 metres) actually use a hub chip, they're effectively a single-port hub according to the system. I think other kinds of usb "boosters" may exist, but presumably as hub chips are cheap that seems to be how active extension cables usually come.
From what I understand an active USB cable can be made with a very simple logic buffer circuit that adds pretty much no latency to the system. I suspect cables using hub chips is either reusing defective hub chips (eg only one downstream port works) or companies that already have tons of hub chips on hand for making hubs to the point that it's cheaper to use those than it is to also stock buffer chips.
Linus: "something is depressed"
Tanner: "oh... Sorry"
Linus: "no not that kind"
I felt that 😂
I loved the video for being so educational as many pointed out, and I also love Tanner's energy. Props to this man for the joke at 22:48. Although depression is not a joke, but an illness, being able to chuckle about it is what makes your life a bit brighter. Thank you, Tanner, this one made my evening.
Same I hope to see more of him in the future.
He also has a mouse infestation
🐁
One of the best videos you've made. Theoretically understood all of the limitations, but to actually physically test this just looks like amazing fun! And the AMD tests are just damn bizarre and awesome!
I love AMD's yolo approach, it has saved me time and effort in the past.
Me over here using 3,094 USB devices on my desktop with a custom intel chipset designed for my pc and my pc only.
i don't think its an extremely powerful USB host i think its just more bugged than tanking because none of those actually worked AMD is still very buggy for no reason
@@kieranlee9610 its more that the y will let you pile it on until you crash. It gives you a little bit beyond the official standard, whilst simultaneously becoming exponentially more buggy the further beyond the standard you go.
basically, mad scientists
22:34 The delivery just cracked me up.
personally, i just love the look on Linus face 2 minutes in when he's like "Wait this mouse is hot?"
The look and voice that screams "i was expecting to possibly break something today, but not this quick and why in the HECK would it be the MOUSE of all things?"
Sher he Holcked it out quickly, but the momentary confusion just gets me.
15:39 That implosion was weirdly satisfying to watch.
The limit is not the number of devices but the number of endpoints per hub controller. With newer USB 3 you could connect up to 4096 endpoints. Intel xhce controllers are famous for not complying with that limit, furthermore different versions of the chip have different limits ranging from 64 to 192. AMD supports a lot more of endpoints.
If intel figures out a way of saving some money so one of their theoretical limits is lower but they don't think anybody in the real world will complain about it, they will do it.
Intel Sucks
"nobody will use more than 64 devices at once" intel laughed while not seeing Linus Sebastian quickly approaching behind them
@@KainniaK I think its fine so long as they include it in their documentation (I don't think they do tho)
"Intel xhce controllers are famous for not complying with that limit"
There is no non-compliance there - and it is xHC*I*.
Along the same lines of this video, I would love to see the team investigate the USB 3.0 interference with 2.4GHZ devices (such as wireless USB dongle mice, & bluetooth even).
A fantastic hub! Have had one for the last couple years and the speed is great and not one issue at all.... A great video!
This is absolutely insane, and I love it! I don't have enough USB ports on my system so I've always been interested in getting a powered hub and that 16 port looks awfully interesting now.
What the hell do you need 16 more usb ports for lmao
@@D3nn1s I see someone has never made a USB RAID device Just Because™
@@D3nn1s music production
@@D3nn1s a flight simulator cockpit.
Ikr man
2:21 *POV No nut November is over*
LOL
Doing all that work for nothing Lol
This video is very relevant to my work. I got 20 port powered hubs that take 2 usb B 3.0 inputs. (basically two 10 ports hubs in one unit) I flash 40 galaxy phones at a time and it takes forever because of the bandwidth, pushing 7.5 GB to 40 devices. I have 3 usb PCI cards so basically 10 ports per controller. I would love to flash more at a time but wasn't sure where my bottleneck is
Why the f are you flashing that many phones? Spam bot?
Are you the reason so many bots exist?
i never heard of something like this. why do you have to flash so many phones???
@@dedtrox6424 the guy that flashes the stolen phones...
@@dedtrox6424 Probably the work phones for the company they work at. A lot of companies use them.
The editing in this video is on point, the yee dinosaur, the monty Python skit, whoever edited this is a master of memes
Linus semi panicking about the hot mouse was pretty amusing
Tanner is such a master of the deadpan delivery. I love it.
I remember back in the days before USB, we used serial ports, and a PC would likely have one or two, and the most I saw on one system, with a controller that cost more than my gaming PC at the time, had 8. The resources used by each port pretty much limited it to 8 ports per system. Having so many devices today is such a luxury.
I worked at a place in the late 90:ies where we had loads of more serial ports than that on a single pc, the trick is having the kind of cards that offloaded some of the processing to the card itself. It was used to run a modem pool, but I think that I remember it being the same number as you, aka 8 per card.
Yeah, I remember reading one of dad's old "how computers work" books, and it talked about SCSI daisy-chaining (the predecessor to doing the exact same with USB)... Apparently, you could make some real crazy stuff happen back in the day if you had enough devices, enough cables and ports, and zero fscks given.
serial and rs232, those were the days, not forgetting the parallel printer port.................
@@skeennah1927 Ever have to deal with RS485?
@@dangingerich2559 nope, haven’t heard of that
Here's an idea remove every keyboards key caps and line them up for a light show that is worth an entire video😮
I found this out a few years ago! Depends on the system! Also, some Unraid systems wont boot if you have so many USB drives in that it pushes the bootable USB off the boot device list.
Lol, that sounds like a fun headache. I recently changed motherboards and there are physical slots for 8drives but the silicone only supports 6, so when you turn it on it would randomly select 2 drives and not detect them. I figured it out quickly enough, but didn't notice this at time of purchase and needed to buy a raid card.
...you could say...It got booted 😉
@@ErulianADRaghath lmao get out :-p
@@Idiomatick Yikes, that also sounds like a headache and bad design!
@@CyberbrainPC It was clearly written in the spec so i have only myself to blame..... though a better eufi diagnostic message would certainly be a welcome improvement. I tried switching cables before checking spec, so i guess it'd have saved me 10mins.
15:00 this makes me feel better about my cable management
This is what I live this channel for. The crazy stuff I always wanted to ask but nobody reasonably had the resources to try. Except you guys...
6:44 Okay but drop the motherboard info. Need one that'll work with what it's given. I'm not dainty with my stuff so I get extra-reliable, extra-durable versions whenever possible.
10:30 It seems like you guys forgot about the USB-BC (battery charging) spec which allows basically any USB-A port to pull a much larger current than the USB 2.0 and 3.0 specs originally allowed. In some cases, up to 2.4A for a total of 12W. This is why USB-A charging stations often have 2.4A ports. The USB-A plug is supposed to be able to handle 3A without catching fire to remain in spec. Whether or not the host controller allows that much is another thing.
When phones started to have "quick charge" 5-7 years ago it wasn't uncommon to see 5V 5A chargers with a USB A plug.
@@bastienx8 I've never heard of that, do you know of any examples of devices that would actually draw 5A at 5V? Seems like a fire hazard...
@@Cyberguy42 The Huawei P20 Pro and P30 series were shipped with an official Huawei fast charger with a 5V 5A port, and a corresponding "5A" USB A to C cable.
The Oneplus 3, 5 and 6 had a 5V 4A charger, for example
Doing the real testing that actually matters in this world. Love these guys
Yeah I really wanted to know if I can plug in 1000s of usbs in my computer
Linus - Genuine idea for a video. Do a USB hub rundown of cheap or unbranded hubs compared to good ones. I recently bought a hub marked as USB 3.0 and when a USB 3.0 device was plugged into a USB 3.1 port via this hub it slowed the data transfer down to USB 1.1 .... It was clearly a con, but there are thousands of sellers trying to flog them with dodgy misleading descriptions on eBay and Amazon (who don't care). Call the scam products out and do a wonderful consumer awareness video all in one 👍
To be honest powered cheap USB hubs kind of scare me. I've seen some actually send voltage down from the hub into the motherboard. You got to even watch out for some USB devices having malicious firmware which may have keyloggers on them. I just buy directly from trusted manufacturers for things like USB devices, SD cards, etc. Found that out after getting scammed with a fake Samsung micro SD card which looked legitimate until I started running some tests.
Another challenge connecting 100+ input devices is it'll only take one with one stuck button or key to cause issues, let alone all the razer-like devices auto-installing software next to their drivers it's still mindblowing you managed to get so far!
Would love to see how linux tries to deal with this. You're not limited to 26 drives there.
lsblk would run for a solid minute
Linus is in his side-missions era… Should’ve left the CEO position sooner 😂
A lot of these crazy videos are coming from tanner which is amazing
So true. I love this kind of content. Like it might seem just fun and trivial but I actually feel like I learned useful stuff from this.
Wait what he's not CEO anymore?
@@jswclips8459yeah, he stepped back and let his former boss take his place, so he can completely focus on content creation again, without the whole headache that comes with being the CEO of a multi million dollar company
@@jswclips8459 Nah he hired someone else as CEO so he can do the stuff he really likes in the company. He's like, Chief Vision Officer or something like that now?
23:03 His face is like: What (tf) am I witnessing???
AMD knew Linus was coming, and said we accept your challenge.
6:46 mother board acting like a real mother
22:31 Yeah, we have a mouse infestation. 🤣😂🤣
This actually provided A LOT of insight on some of the USB issues I've been having. Hat tip, boys!
Brilliant video, one of the best for a while! This is the type of content that makes me excited to learn more about computers, like yeah, how does the USB spec actually work?! Props to the writer he did an excellent job and he's a great on-camera personality too!
Ben Eater has a great video where he discusses the basics of USB electrically. He also debunks ps2 vs usb latency a bit.
I love the fact that the video turned into "Let's see how many devices we can plug in until it stops working" to "HOLY CRAP WE'RE SO MUCH PAST THE LIMIT AMD WHAT THE HECK"
Ah yes my daily life plugging hundreds of usb devices. I do that every day I mean who doesnt?
For USB storage devices : In windows you also have the drive letter limit, so you cannot add more than upto drive Z (I think there was a hack to be able to also use drive letters A and B which are for floppy disk drives). In linux though there is a possibility that it might work.
There is no limit in Linux, you can have as many drives as your IO can handle.
Wouldn't linux also be limited in the same way because each drive is sda, sdb, sdc, and so on?
This is true only for drive letter assignments, windows allows attaching disks to empty folders just like Linux does, and can address a nearly infinite number of volumes this way.
@@regrettspaghettt No - Linux wraps around at sdz to sdaa, sdab etc, and then will move on to sdba after that until you reach sdzz at which point it will go to sdaaa and so on.
In windows you can mount drives to folders Unix style, using disk manager.
In disk manager, right click on the drive, select "change drive letter and paths" remove the drive letter(optional) and in "add" you will see an option for "mount in the following empty NTFS folder"
With all the new lab equipment I'd love to see a test of lots of different dashcams, see if the expensive ones are worth it 🤔 *edit: didn't realise they've already done one, maybe a more in depth one or possibly diy jank one 👀
I'd also like to see it done with Linux, which might handle the USB connections slightly better. If anything, maybe to disprove it as well?
they have already done a video on dash cams, and their result was pretty much none of them are, i would like to see a more indepth one tho, as someone who is looking to get their first car soon i definitely intend on getting one
they made video about them already
there is difference between 50-300$ in quality but more expensive are useless, better using some custom solution for really high end systems
They already did a dashcam video, although they can now do it more in-depth but yeah they already did
I really want to listen to Linus talk more about hubs
I've just gotta jump in here, who the heck needs a heated mouse?? @ 2:31
I'm a bit late, but it could be because some people may have really cold hands. For example, going outside in winter, standing in front of a fan, or having a cold snack.
When I saw the start of this video I was expecting weirdness with keyboards being more than one device per keyboard. I was not expecting you to not think of it "live" in the process. Early on I learned in device manager keyboards do this for n-key rollover while messing with a keyboard that had 6 key and n key rollover (would switch from being 3 and 6 devices in software). It was very fun to watch the issues occur in real time.
It would be interesting how a different kernel (like Linux, Linux ZEN, Linux mainstream, Proxmox, Unraid, etc.) would handle it. It would also help Server owners that work with virtual computers and real I/O hardware (GPU and USB passthrough).
All of those use the Linux kernel, though it's possible the OS itself would have an impact. As far as different kernels, FreeBSD would be an option
this was one of your most fun technical videos with actual application in normal people's daily life. thanks.
@14:31 "Theories will only get you so far"
This was filmed the Thursday before LTX. The janky mess of keyboards and usb hubs was in the floatplane tour video. I'm guessing Linus is taking some time out to recover from the LTX madness.
Or perhaps things take a while to edit and things are built up to have a cushion?
@@Poverty_Welder I know there is a buffer but this seems longer than normal.
Just to ellaborate more on the limits: The upper limit for devices in a single USB network is, per the USB specification, not xHCI, 127, as correctly stated (128 from 7-bit address length, but address 0 is reserved for any un-enumerated device so the host can talk to them and enumerate). xHCI for some reason allows up to 255 devices (8 bit address) but I can make no sense of how it would actually work, because USB simply can't handle more than 127 because of the address size, maybe 2 separate networks in a single controller, each on a separate port, but I've never seen it. Each device can have up to 31 endpoints, also per USB specification, not xHCI (that's 16 from 4-bit endpoint address, but each endpoint address except for 0 can have one IN and one OUT endpoint. Endpoint 0 is special because it's a single IN/OUT endpoint exclusive for the control channel). So the absolute upper bound (for a single controller) is 3,938 IF you consider 0IN and 0OUT as a single endpoint (device 0 always has the 0 address endpoint). No controller I know of actually reaches anywhere close to this, so you can have anywhere from 96 (for Intel chips AFAIK) or even lower for embedded MCUs for example, but there's no reason to stop at 128 really. The reason host controllers have endpoint limits but not really device limits (lower than USB capabilities of course) is because each endpoint usually requires a dedicated FIFO queue in RAM to handle communications, whereas a device is just an address number. Also in some controllers endpoint 0 is implemented as two separate endpoints because it makes more sense as it needs both IN and OUT capabilities so the actual endpoint limit may be lower than it seems
2:22 "WITH THIS TREASURE, I SUMMON *THE HUB* "
- Megumi Tech Tips
Id love to see you guys do a followup showing what kind of damage could be caused by overdraw on USB ports (not so much fire, but degeneration of motherboard parts/ports/etc.
How does this effect the longevity of the devices being used, etc.
I once saw a computer with 120 USB ports at a hardware exhibition in China, and I'm not sure that so many ports could work at the same time. This machine was designed to be used to manage a fairly large number of USB hardware keys for social insurance accounts at the same time.
I love these experimental videos that i always wondered about in the back of my mind but couldn't replicate at home 👍
AT 8:49 I came to realize Linus is the Bob Ross of computers.
14:53 don't call me Surely
Another reason why an unpowered hub might want to allow hubs to be connected to it is because some keyboards are actually hubs. As in your keyboard will be a keyboard connected to a hub connected to your computer (where the keyboard has other usb devices or ports on it)
I’ve had issues with plugging in too many hubs rather than too many devices which is interesting. Having the same amount of devices plugged into two hubs seems to work better than having them plugged into 4 different hubs. Also some hubs work almost flawlessly whereas others just keep dropping out when I connect thumb drives to them but peripherals work fine… USB stability, even more than the instantaneous number of devices you can have plugged in, is a big issue and it would be worthwhile to investigate stability in a seperate video. I will say that having a seperate usb controller via pcie definitely improves stability! I’ve noticed that. But when I plug in multiple external hard drives I have significant problems with them just disconnecting intermittently even if they are on seperate controllers (this happens more often under high bandwidth usage but also seems to happen even if I’m just using the drive a little bit??). I’ve noticed this issue on different devices; my old Dell intel 7th gen i7 laptop and on my X99 5820k PC. 4 port powered hubs seem more stable than 7 port powered hubs and 7 is more stable than 13 port hubs; but I have another specific 8 port hub that isn’t sold anymore and for some reason is super stable. Maybe stability varies on vendor or newness of technology like Linus noticed on AMD vs Intel. I wonder if there’s a measurable difference on USB stability and % uptime on Windows vs Mac or from vendor to vendor
There's definitely a difference between the chips in different brands of hubs. We used to run in the same issue doing backups to multiple external drives and we didn't try and copy something to all the external drives at the sane time but rather one after the other and we figured out that some powered hubs just are better than others and actually motherboards as well. We eventually also fixed it with a board with a bunch of PCIe slots and USB cards as opposed to USB hubs. Laptops on the other hand are all over the show and some laptops (modern and old) just really don't like having a bunch of USB devices at the same time.
It's all fun in games until you have to untangle the wires and put everything away
One of my favorite videos in a while. Awesome job LMG team!
That motherboard probably has a different host controller for each of those USB ports they are using. Some better motherboards give you one host controller per bank of ports, other motherboards give you just one host controller for all the USB ports.
That doesn't sound right. Name a motherboard with a host controller for every port.
@@DanKaschel Where did I say "for every port"?