CPU fan speed doesn't change

[Growltiger]

I have a three year old Asus P6T Deluxe V2 motherboard with an i7 920. It is warmer than it should be. (Idle 47C, 82C when running Prime95.) Only slightly overclocked, BCLK=150 instead of 133).

The cooler is a Thermalright Ultra 120 1366RT eXtreme CPU cooler with 120mm fan.

The fan speed doesn't change, it stays at 1500 - 1562 rpm. I understand that this fan is not capable of changing speed, although it does report its speed correctly to the motherboard.

Is there any way to change the fan on this cooler so that it changes speed? Would this help? Thanks.

 

[Conumdrum]

Yes, get a PWM fan like an Scythe AP-29 and plug the PWM connector into the mobo and set up your bios to control it.

 

[Growltiger]

Thanks. Two questions.

1. That fan seems to have a 4 pin molex plus a three pin PWM connector. My motherboard has the standard 4 pin CPU fan connector. Do I assume it needs a standard power cable to the 4 pin, and the 3 pin connector goes the to 4 pin CPU fan connector? (Why does it have 4 pins when only three are used?)

2. How do I connect a standard shape fan like that to my Thermalright cooler? The fan it came with has fingers that grip the fins. I can't see how I would fix that fan to it?

 

[Conumdrum]

Your fan is then not PWM controllable. Have you looked at the mobo Bios or the software that can control the fan speed? Your fan has two connectors. One is just two wires (12VDC) from the Molex. The small one is 12VDC and an RPM wire, usually yellow.

Your mobo could be voltage or PWM controlled, maybe. That's up to you to figure it out and see if you can use the mobo to change the RPMs on the fan. Read your manual, do some searches on fan control on that mobo.

You fix the fan to the cooler with anything you want to use. Zipties, tape, whatever.

 

[Growltiger]

My two other fans have 3 pin connectors. They must be altered by voltage.

The existing CPU fan also has a 3 pin connector. It reports its speed but does not change speed regardless of BIOS settings. So I assume the BIOS requires PWM control for the CPU fan.

The CPU fan connector has 4 pins. Ground, Power, In and PWM.

The fan you suggested instead has two connectors. The control one has three pins not four. That is what I am trying to understand.

 

[Conumdrum]

Sorry, I mean this one: And you have to mod it.
http://www.overclockers.com/forums/showthread.php?t=702137&highlight=ap30

Or buy any quality 2000 RPM PWM fan.

And read this for fan suggestions:
http://www.overclockers.com/forums/showthread.php?t=709786

 

[Growltiger]

Thanks, I will learn more about fans.

 

[Conumdrum]

Last thing. Some mobos have PWM and voltage controlled. Have you even looked at the bios, your manual etc? I did, it's not clear, so I assume it's 4 pin PWM only. And the mobo comes with software to adjust fan speeds. Yours is ASUS Fan Expert. You have it installed? Give it a try?

 

[Growltiger]

I've read everything several times... I agree, reckon the mobo allows 4 pin PWM control only. The current fan has a 3 pin lead, so it just reports the speed. I have tried adjusting the speed from the mobo but it never changes. I have no problem adjusting the speed of the two case fans, which have 3 pin sockets so must be voltage controlled.

In any case that fan is rated as 1600. If I am to get more cooling aI need a faster one.