2 vs 3 vs 4 Pin Computer Fans Explained (and Which Should You Buy?)
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- เผยแพร่เมื่อ 8 ธ.ค. 2022
- You've likely noticed that there are several types of PC fans, with a primary differentiating factor between models being whether they are 3, 4, or sometimes even 2 pin.
What do these pins do? Are 4-pin fans worth the price premium over their 3-pin counterparts? Does it make any difference? Today I'll be investigating the unassuming topic of PC fans. We'll investigate how modern PC fans are powered and how this has evolved over the years.
I hope that this explains misconceptions around this, you learn something and enjoy the video!
TLDW:
2 pin fans - give them power and they run
3 pin - 3rd pin allows RPM sensing and failure detection, speed control by changing voltage to power pins
4 pin - give fan 12v power and a PWM signal, it figures out how to run motor, and has rpm sense.
Music Used: Their Story by Approaching Nirvana (with weird artifacts due to kdenlive)
Produced by Tony Tascioglu
tonytascioglu.com - วิทยาศาสตร์และเทคโนโลยี
Apart from giving useful information you come straight to the point AND you avoid that artificial excitement so many others present these days . I like your videos very much.
Thanks for the kind words!
Your videos are never useless Tony. Keep going. I'm glad I subscribed many moons ago. Always learning new things from you. Thanks again 👍
Thanks for the kind words Conor!
Awesome video!
May your channel gather many more fans.
Thank you, great explanation... I just brought a turing pi, which has a 2 pin header, and the case I've brought has a fan with a 3 pin header, I think the turing Pi can set the output voltage... but now I know, no monitoring or PWM.. thanks again
I seen a video were they used 3 mosfets , 3 diodes, & 3 transistors . The wires from the 4 wire fan were hooked up black wire to black wire the 3 other wires into the mosfet holes were they bolt to the heat sink . The red power wire is feeding the pin sides along with the diodes and transistors . They are wired from one mosfet to the next . I didn’t see how it could work because the motor wires were on the heat sink side of the mosfet . It made the fan look like it went from 3000 rpm to like 30,000 rpm . Thanks for this video it help me determine my 3 wire fan canon be speeded up . I’ll just have to get a 4 wire one an go from there . Thanks again , you did a great job explaining it in detail !
Thank you! I’m glad I came across this channel!
Good job on educating on stuff which seems trivial at first but is important to pay attention to
Thanks for the kind words!
Molex is a company who make a myriad of connector types, not just the 4pins from pcs. Their extremely helpful and can be utilized to make some incredibly cleanly wired installs.
Super helpful video, thx!
really helpful, keep up the good work.
Thanks for the kind words!
Thank you Mr. Taşçıoğlu
Interesting, thank you! 👍
Not useless. This was exactly the sort of info I was looking for, to help me rig up a fan to circulate air from within my apple iie which I just installed the RAMWorks II card, which evidently runs pretty hot. ❤
Thanks for the info!
Glad you found it helpful!
I have noctua 3 pin fan. Red, black, yellow. I also bought a dimmer to adjust the speed of the fan. The fan is coming to my camper toilet for ventilation purposes. I dont know if I connected it correctly, red and yellow together to the 12v and black to ground. The dimmer only slows down the fan very little. Same without yellow connected anywhere. Whats wrong? Should I leave the red disconnected completely and connect the yellow to the 12v or what? Can you help me?
I'm working on a DIY Desk Fan using a 120mm 4-pin CPU fan. With a standard Red/Black wire power supply, what wires would you connect to that? Red to Red and Black to Black? I would assume I don't need RPM or Speed readings as its just for a little desktop fan. Looking at a Noctua 120mm 4-pin fan
For a 4 pin CPU fan, the yellow wire will typically be +12v and the black wire will be ground. You don't need the RPM pin (pin 3) or the PWM pin (pin 4) hooked up for it to run - however, if you don't use a PWM signal on a 4 pin fan, it will always run at full speed, and 4 pin fans typically do not like speed adjustment by just lowering the voltage and want a constant 12v supply.
To clarify, on ATX computer power supplies, red is +5v and yellow is +12v. So, to answer your original question, if the 'red' wire on your power supply is +12v, just connecting power and ground should work and will let the fan run at full speed.
If you do need speed control, the PWM pin on 4 pin fans is typically only rated for 5v, not 12v - so if you do try to adjust the speed with the 4th pin, you might want to make sure you don't overvolt it.
Sorry if this sounds confusing, let me know if I should clarify anything!
Thanks, for electronics begginers like me this is awesome
Glad you found it useful!
Thanks
Thanks a lot.
Curious on the 3 wire. I have an Artic Tricool that I am going to use as an exhaust fan in the camper. With just red and black connected to a 12v battery it barely ran. I connected the yellow and red together and it ran perfectly. Any idea why? Want to make sure I am not going to burn it up.
I don't have a good answer for you at first glance. I would be curious about the position of the wires in the 3 pin header than the colour - while in most applications, red is the input voltage and black is ground, in the PC world, it's typically red=5v, yellow=12v, so that yellow wire might actually be the +12v input for the fan rather than signal.
In either case, it probably won't burn it? Most electronics are better these days at ensuring you don't backfeed them or run them with reverse polarity.
Again! Great content.
Thanks again!
I appreciate this, thanks so much
Glad I could help!
thanks bud. I can't say I understood why u can't turn the power on/off on 3 pins fans. But I got the point, thanks for that. Is there any way to know that my MOBO can regulate speeds with 3 pins fans also? (it has 4 pin connectors by default) it's b550 tomahawk from msi.
Again, thanks for this video and I hope to see your reply!
Most motherboards these days will have 4 pin headers, but will support both DC voltage (for 3 pin) and PWM (for 4 pin) fans. Most auto detect if you use 3 pin, and switch to DC mode, but on my last board, you had to set a switch in the BIOS where you configure fan curves to mark them as 3 or 4 pin (DC or PWM)
@@TonyTascioglu yeah my motherboard X470 Aorus Ultra Gaming-CF has 4-pin headers for fans (4 system, 2 pumps, 2 CPU) and I plugged in four 3-pin system fans and their speed is controlled fine with the SIV program. It has full programmable profiles for each fan, power% per temp.
BTW are I see you are in Canada, are you Greek or Turkish by chance?
Also, I think, if you take apart the heads of the fan cables, you can connect the 2 power wires (red and black usually) directly on a molex. If on the molex the black is ground, red is 5 Volts and yellow is 12, then you can get 5 or 12 Volts to the fan, but also maybe 7 Volts too. If you plug them on the red and yellow molex cables then 12 - 5 = 7 , right?
What about the fan which connected by 3 pin but with PWM instead of Tachometer pin? Will it control by PWM signal without a tacho signal?
3 pin fans typically don't allow PWM control. From all the ones I've seen, the 3rd pin is always just the tach, and you can't give PWM on the voltage pin either, as PWM fans need 12V on the input with the PWM signal on pin4, and it converts it for the motor internally.
Wanted to know if I'm getting speed control from my case fan headers. I guess not, 3Pin connection for a high RPM pmw fan would be a waste. So now I need to get a fan hub because the board itself doesn't have enough 4pin headers 💀. Thanks a lot for the info
Whether you have speed control on 3 pin headers depends on the motherboard as they work by just lowering the voltage to the power pin (with the 3rd pin providing the feedback on the current RPM). From my experience, most consumer boards do have the capability to provide a variable analog voltage output from the 3 pin header, whereas the Supermicro board I use does not have that capability and runs all 3 pin fans at 12V.
I bought a Case that came with 2 fans with 3 pins each, and a splitter. Is there any problem if I connect those fans to that splitter that has only connections with 2 pins?
It will most likely work - however, if you are only hooking up 2 pins to a motherboard, you might not get the RPM sensor which stops the motherboard from controlling speed in most cases. If your splitter is 3 pins to 1 fan, and 2 to the other, it should work (but both will run at the same speed).
On the other hand, if the source of your splitter goes to the power supply directly (instead of the motherboard), it will also work fine, just without speed control.
@@TonyTascioglu thank you for the reply!
hi tony, I bought 12v 2 pin fan(black and red wire), there is no problem if I put in the 4 pin? and tell me which 4 pin compatible. TIA new subscriber here.
For starters, you likely won't have speed control over it (theoretically possible - but most firmware won't let you unless you have and RPM sense pin hooked up), and your motherboard won't detect or know that you have a fan connected there. Whether it works depends on whether the motherboard outputs a constant voltage to the fan headers when not in use.
In the worst case, you can always buy a 2 pin adapter and adapt a sata or molex power supply connector (which have 5v and 12v) to the fan directly.
HEY can i use L298N and arduino to controll the speed of a 3 wire fan
Why are you not showing the GD Plugs?
Fan noise is not related to 2, 3 or 4 wires. It depends on blade design.
Actually there is no need of all this fancy PWM controllers to run a cooling fan.
Al that PWM does is regulate the speed depending on the temperature of what it is cooling, just saving some minuscule amount of power.
Really fans are BLDC aka brushless that have a embedded control circuit as its a multipole brushless fan. So the circuit can be voltage controlled with PWM but the fan curve is sort of limited with some 2 pin fans as was never designed to be voltage/pwm controlled.
4 pins with a pwm input and tacho out are what they are.
3 pin fans just have tacho out with a circuit that is designed for voltage control.
There are also now for Pi like boards gpio fans where they are 3 pin but the 3rd pin is a PWM input not tacho out.
Why 4pin pwm fan are much higher amperage rate compare to 2/3pin dc fan? At Same size, same peak speed. Most 4pin pwm rated 0.30a above
It can be the same speed in RPM, but have much higher static pressure. Eg: You can find 3000 RPM Delta server fans, which can pull over 1A, but it's still only 3000 RPM, which isn't much higher than a normal fan.
Can i connect 2 pin fan in 3 pin socket
Depends - as long as both are 12V, if your motherboard supports it, yes, but some won't give a voltage unless the tach pin (pin3) is also populated. And if it does work, you likely won't have speed control.
Can i use cpu fan in gpu
Yes and no. I mean, if you can mount it, there's no reason why not from a physical standpoint.
The only problem is you'll want to make sure the fan speed is controlled by the GPU.
ie: if you replace your GPU fans with Noctua fans, and plug it into your motherboard, the GPU fans will spin up and down with CPU temperature, not GPU. So, if you can plug the fans into the GPU or solder it to the older fan connector, it'll be better as the GPU will be able to set the speed based on its temperature.
Useless is right!
There isnt friction in a brushless cpu fan except for the sealed ball bearings. Lol. Go back to school bro.
I have an asus prime b450m a 2, andni have some old 3 pin fans, you think will be ok or i need 4 pin ones ?
is not useless.....thks for this..