CPU Fan. Does it have to have 4 pins??

Notorious Lee · 14 Jun 2008 at 18:12

Hi,

I have just installed the Thermalight 120 extreme hsf.

I purchased the 120mm fan seperatley because it doesn't come with it.

However, the cpu fan connector on the mobo is 4 pin & the fan connector is 3 pin.

I can still connect the fan to 3 pins of the cpu connector on the mobo but is this meant to be?

Cob · 14 Jun 2008 at 18:23

A 3 pin fan is fine. There should even be a little tab so you can correctly line up a 3 pin plug.

p4radox · 14 Jun 2008 at 19:04

Yeah 3 pin fans are backward-compatible with the 4 pin socket. I think the 4th pin is for PWM control.

Pneumonic · 14 Jun 2008 at 20:44

3pin into a 4pin works but you will find you wont beable to control the speed of the fan.. if you want to control the speed of the fan you are best to use a 3pin connector on the board..

PhillyDee · 14 Jun 2008 at 20:52

My gigabyte has the option of PWM or Voltage regulation. So they recognise both ways of doing it.

Yewen · 14 Jun 2008 at 21:21

PhillyDee said:
My gigabyte has the option of PWM or Voltage regulation. So they recognise both ways of doing it.

Most boards do it this way is my understanding.

What board do you have specifically?

Notorious Lee · 14 Jun 2008 at 21:29

I have the Asus P5N32E-SLi.

Does this mean I won't be able to use the q-fan feature?

Pneumonic · 14 Jun 2008 at 21:35

I have a P5K-E which doesnt like it, also had a few problems getting speedfan to work a 3pin on the 4pin CPU connector on a DSR-3 depends on the board I guess

p4radox · 14 Jun 2008 at 22:54

Pneumonic said:
3pin into a 4pin works but you will find you wont beable to control the speed of the fan.. if you want to control the speed of the fan you are best to use a 3pin connector on the board..

The 4th pin is for PWM speed control. You can still control the speed of the fan via standard linear voltage regulation.

Notorious Lee · 14 Jun 2008 at 23:06

What is PWM speed control?

Also, will only having 3 pins restrict me from using q-fan.

Deluxe1 · 14 Jun 2008 at 23:23

Is there such thing as a 3pin to 4pin converter?

Bigdogbmx · 14 Jun 2008 at 23:54

I dont think thats possible as the fourth pin is a complete seperate cable going to the fan.

BlackBat · 15 Jun 2008 at 00:47

"What is PWM speed control?"

Pulse Width Modulation

Tuvoc · 15 Jun 2008 at 09:37

Notorious Lee said:
I have the Asus P5N32E-SLi.

Does this mean I won't be able to use the q-fan feature?

With my P5N-E I used to have a 4-pin and the QFan feature worked perfectly. Now I have a 3-pin, and it doesn't work at all. I'll be getting another 4-pin fan.

Pneumonic · 15 Jun 2008 at 11:29

PWM basically turns the fan on and off very quickly which means that in general a PWM fan can run at smoother and lower RPM than a voltage controlled fan.. as I say from my experience the ASUS P35 and X38 boards only have the option of PWM control on the CPU fan and therefore if you want to control a 3 pin fan you will need to run it off one of the chasis fan controllers