Does PWM work independently of Q-fan?

Alfie

Alfie

Alfie

Associate
Joined
4 Dec 2008
Posts
1,620
Location
Sheffield
I've got 2 case fans and 2 push pull fans on my heatsink, all connected via one PWM header. Are the fans controlled by system temperature even when Q-fan is disabled in the bios. What does Q-fan actually do?

Thanks.
 
That's a lot of fans connected to one header, I'd be careful mate, just incase you fry the fan header on the mobo..

Which board is it you have?

I know the Gigabyte UD5 has issues with PWM control, I have 2 of them, and on one of my boards, PWM doesn't work at all, whereas on the 2nd one it has worked perfectly since F4 BIOS.
 
If you use 2 of theese cables here.

http://www.overclockers.co.uk/showproduct.php?prodid=CB-031-AK&groupid=701&catid=48&subcat=

You can run 5 pwm fans, no power strain is placed on the mobo's cpu header, power comes direct from your psu. All that the cpu fan header does is provide the pwm signal to control the fan speed, depending on your motherboard brand their should also be software that will enable you to tweak the fan profiles, asus call it fan xpert which is part of the asus ai suite software.
 
Alfie said:
What does Q-fan actually do?
Click to expand...
Q-Fan is a set of fan RPM vs Temp presets . .

Alfie said:
Does PWM work independently of Q-fan?
Click to expand...
PWM is a method to control the power delivered to a fan, nothing more nothing less. The difference between 4-pin PWM Fan and a 3-pin regular fan is PWM only have two modes, On and Off (full voltage or No voltage), thats how it works. A regular 3-pin fan controller adjusts the fans speed by raising and lowering the voltage, how ever the current is always *on*

Q-Fan tech can work with either 3-pin or 4-pin methods although on some ASUS boards I've used the CPU Fan only adjusts if its a 4-pin PWM . . . which is strange because the other Sys fan ports adjust a 3-pin fan fine?
 
Alfie said:
none of the asus software or bios is compatible with Akasa Apaches on 3 pin headers. They have to be at full speed and it's very noisy! :(
Click to expand...
I saw you mention this the other day and I had a thought, have you checked in your motherboard manual which fan ports have Q-Fan control? . . . as normally not all of them do?

I reckon your using a non q-fan fan port! ;)
 
Id avoid the gelid connector, running to many fans of one header could be dangerous, the one ive linked above is much safer as power comes direct from the psu. I use it to power pwm fans on my rig, a much safer setup.
 
Nah mate, all CHA headers are Q-fan controlled, nothing is plugged into the PWR header as I am aware that cannot be Q-fan controlled. Fact is the apaches wont spin up properly with any Q-fan enabled.
 
setter said:
Id avoid the gelid connector, running to many fans of one header could be dangerous, the one ive linked above is much safer as power comes direct from the psu. I use it to power pwm fans on my rig, a much safer setup.
Click to expand...

What about three fans with the gelid splitter? I've bought them now :( If only Akasa would braid their cable!
 
I wouldnt risk running three, i did run 2 arctic pwm fans of the cpu header once without issue, however when i discovered the akasa splitter i switched to it, i agree that if it was braided it would be even better but mine is hid up at the top of my case.
 
What about a gelid splitter plugged into 1 of the AKASA cables headers? I really need 4 fans off one PWM header. If i'd have known the Apaches would only run at full speed off 3 pin mobo headers I would not have bought them!
 
Intel's PWM header specification allows for 18W maximum draw. Most fans are between 2.5W and 3.0W. Companies that make daisychainable (is that a word?) PWM fans like Arctic Cooling reckon 5 fans maximum although I have 10 running off my ASUS P6T as the FETs they use allow for 24W+.

Even if you do overload the fan header, ASUS, Gigabyte and XFX boards have soft fuses on the PWM header that reset themselves after a few seconds.
 
So i'm safe to run 4 fans off one PWM header on the P6TD with the Gelid splitters that don't have additional molex power? If so, why does the Akasa have have the additional molex power? Will I be ok with 4 Apaches? Are they daisy chainable do you know?

I'm also interested to know what happens if 1 of the 4 PWM fans in the chain is rated for different RPM?

Stick with me WJA96 - Seems you know your stuff mate.
 
You must log in or register to reply here.
Back
Top Bottom