How to change the speed of PWM fans

pilsburypie

pilsburypie

pilsburypie

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So, I have bought and installed the following case fans to upgrade my stock fans:

Exhaust
http://www.overclockers.co.uk/showproduct.php?prodid=FG-009-PT&groupid=701&catid=2331&subcat=1816

2 front fans
http://www.overclockers.co.uk/showproduct.php?prodid=FG-036-NC&groupid=701&catid=2331&subcat=4

With my old stock case fans (3 pin) I had full control of them with the Asus AI suite. This was good as I could have them low and quiet for general internet surfing, and then speeding up for video rendering when cooling is needed.

My CPU fans on the Phanteks cooler are still fully controllable in AI suite. One of the front fans is fully controllable, being able to set really slow and then speeding up as temp increases. But, the other identical front fan shows a minimum of 82% and the rear exhaust 83%. I just can't lower the speed.

I've had a look in the BIOS (not really sure what I'm doing) and the fan speeds are all nice and slow in there, around the 800rpm mark and the PC is pretty quiet. As soon as I boot windows the 2 offending fans boost up to their 80%+ minimum speed and the fan noise understandably increases.

Why is this happening? How can I get control of the 2 offending fans?
 
pilsburypie said:
Doyll. I've not used a PWM splitter. The PWM fans are plugged into their respective 4 pin slots on the mobo.
Click to expand...
Than they are probably using variable voltage, not PWM to control their speed. I have only heard of one motherboard that had PWM on anything but the CPU fan headers. Asus claims their motherboards have PWM on other headers but users have found that to be untrue.
 
Philtor - I shall look at that when I'm back home.

Doyll - if this is the case, then how would I rectify? The Noctua fans I have clearly are able to be controlled under 80%, one of them is able to be controlled fully. Why the other isn't is beyond me.
Is the fact they are PWM fans causing the problem? If I had just stuck with 3 pin fans would that have kept full control as it was previously with the stock fans? If so is it returning the fans for the 3 pin version or can I just remove a single wire myself to make it 3 pin?
 
I do it like this, works for 3 pin and 4 pin fanshttp://forums.overclockers.co.uk/showthread.php?t=18584849

For speedfan, works very well for me
 
IIRC only the CPU header on Asus boards support PWM, the other headers will just run them full speed and (in the case of the boards I have used) not allow you to control PWM fans via voltage like you can with 3pin ones.

You could try getting some wire cutters and snipping just the blue (PWM) wire so the board thinks it's a 3pin fan then it may work. Or just return the PWM fans and buy non-PWM ones, which are usually cheaper anyway.
 
pilsburypie said:
Philtor - I shall look at that when I'm back home.

Doyll - if this is the case, then how would I rectify? The Noctua fans I have clearly are able to be controlled under 80%, one of them is able to be controlled fully. Why the other isn't is beyond me.
Is the fact they are PWM fans causing the problem? If I had just stuck with 3 pin fans would that have kept full control as it was previously with the stock fans? If so is it returning the fans for the 3 pin version or can I just remove a single wire myself to make it 3 pin?
Click to expand...
Here's a guide to using motherboard (or video card) PWM control on case fans
http://forums.overclockers.co.uk/showpost.php?p=26079729&postcount=5

Generally PWM fans perform on voltage control the same as 3-pin fans do. It's easy enough to remove the pwm pin from fan plug. Just depress the silver clip in hole on side of plug and pull it pin out. No need to cut the wire. :D
 
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