Difference between 3pin and 4pin fan connectors?

[thegatekeeper]

Hey guys, im tried both 4pin and 3pin connectors but i never knew the difference. I remember a feature where the fan would go up when the temperature rises and then back to idle when it down again. Is this what the 4th pin does?

Thanks!

 

[edgaraslt]

4th pin is PWM . So the answer is yes. 4th pin does that.

 

[thegatekeeper]

Hehe i thought it did more than that. I never liked that feature, so no loss hehe.

Thanks

 

[tomsresults]

CPU fan with 4-pin connector, connected to CPU FAN header on the motherboard, will enable the BIOS / motherboard software to control fan speed based on temperature.

With a case fan and a 3-pin connector connected to the CHA FAN header, it is the same. You don't really need a 4-pin in this case.

At least this is how it is on my ASUS P8P67 Pro motherboard. I don't understand why or how...

 

[Guest]

3-pin is controlled by increasing the voltage, you can connect a 3-pin to a 4-pin header and change the setting in the BIOS to control with voltage instead of PWM.

4-pin has a fourth pin for control via PWM, some CPU coolers use 3-pins like Noctua, they claim that voltage regulation is better than Pulse-width modulation but who cares.

 

[JackNaylorPE]

Mn96 got it right ... but there are reasons to care

PWM provides several advantages....

1. Low power loss
2. Lower electrical noise
3. Allows fans to run at lower speeds

3 pin fans often won't start if their voltage is below 50%, giving them a limited range of operation. PWM eliminates this as it sends full voltage but uses pulses rather than voltage itself to control fan speed.

 

[Toxxyc]

Sorry for the "thread jack" and "mini-necro". Didn't want to start a new thread...

I know the function and usage of PWM, but I want to know why (that's what I've heard) you can't control fan speed from the BIOS on the fan connected to the 4pin PWM header (be the fan a 4pin PWM fan or not)? I understand that you can control the fan speeds manually from within your OS using some kind of software (whatever you choose), but I don't want another app running if I plug a 3pin fan in the 4pin header to keep the CPU cool, I'll rather keep the plain daft fan on the cooler as is.

 

[AdrianPerry]

Personally i like my case fans connected directly to my PSU for maximum cooling. 5 case fans and the noise isnt really too noticeable so nice to keep my system as cool as can be

 

[Guest]

Close this thread someone/