PWM fans or adapting a 3 pin fan to run via PWM plug ?

steveinspain · 4 May 2009 at 15:59

I currently run all my fans from molex connectors and am wondering if it is possible to fit the HSC fan to the mobo CPU socket, thus giving me automatic adjustment via the mobo heat sensors 0 do I need an adaptor, or is it a special fan ?
Fans are Noctua if that makes any difference..

Cheers

siumatfung · 4 May 2009 at 17:38

you could just control it via a 3pin socket on the mobo:d think some ppl use speed fan to control there mobo fans

Louis_Y · 4 May 2009 at 18:02

PWM fans are a special type of fan unfortunately - I think they have some inbuilt circuitry for control using the 4th pin. I've just run into the same issue replacing my stock Xigmatech cooler fan with a Noctua - my P5Q Pro won't control 3 pin fans on the CPU header by altering the voltage like my old DFI mobos did so it's stuck at 100% all the time. Fortunately it isn't very loud at all so I can live with it but it seems like a backwards step in mobo design if that's the way Asus are going.

Some manufacturers may let you use either, possibly requiring a bios setting change to switch between PWM and traditional voltage control on the CPU fan header.

setter · 4 May 2009 at 18:27

Asus boards of late have done away with 3 pin fan control on the cpu header, i use three pwm fans with this adapter on my asus p5q deluxe.

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

Powered of the molex from the psu, and connected to the cpu header, im able to control 3 pwm 400-2000 rpm fans with the asus qfan function.

Louis_Y · 4 May 2009 at 19:04

That's a nice find, setter. I'm tempted to try one but I'm not sure what it would do to my cable management and the Noctua is barely audible even at full pelt. Maybe I'll stick one in the next order I do just to experiment.

setter · 4 May 2009 at 19:15

Dont think itll work with a 3 pin fan unfortunately. Im currently running three of the new sharkoon silent eagle se modular fans through this cable. Unlike previous sharkoons theese come with detachable 4 pin pwm cables or different voltage regulating molex adapters.

ecat · 4 May 2009 at 20:49

Worth checking the manual. My Asus has a 4 pin fan header for the cpu but it appears to detect when a 3 pin or a 4 pin fan is connected. For 3 pin it varies the voltage, for 4 pin it drives the pwm signal, at least I assume it does, it certainly controls the speed of both types of fan.

steveinspain · 5 May 2009 at 07:50

setter - can you tell me exactly which sharkoon fans you aare using - the ones shown here don't mention PWM...

http://www.overclockers.co.uk/showproduct.php?prodid=FG-005-SH&groupid=701&catid=57&subcat=
However, I may just stick on eof the Noctuas into a 3 pin socket and use speedfan as siumatfung suggests.
Cheers all !

PaulyD · 5 May 2009 at 10:43

You can use speedfan as well to increase the speed of the fans depending on the temps you link it too

steveinspain · 5 May 2009 at 11:11

Just seen the Sharkoon fans on their website - looks like OcUK doesn't sell them..

PaulyD - how do you link temps in speedfan - is it easy ?

Louis_Y · 5 May 2009 at 17:06

Well just tried speedfan 4.38 and Asus AI suite Fan Expert and it appears that nothing can control a 3 pin fan on the CPU_FAN 4 pin header on a P5Q Pro. There's a thread somewhere on the speedfan forums regarding this, and I think they're working on it but don't know if it's possible. Ho hum.

ecat - what model of Asus mobo do you have? I have a feeling that the older ones probably support voltage regulation of the CPU fan according to CPU temp, but they've removed it from the newer models

PaulyD · 5 May 2009 at 17:26

steveinspain - I used a different guide before but found this one quickly which will do the job, was a right pain in the **** when I did it!

http://www.addictivetips.com/window...-and-change-the-temperature-of-your-computer/

setter · 5 May 2009 at 17:35

steveinspain said:
setter - can you tell me exactly which sharkoon fans you aare using - the ones shown here don't mention PWM...

http://www.overclockers.co.uk/showproduct.php?prodid=fg-005-sh&groupid=701&catid=57&subcat=
however, i may just stick on eof the noctuas into a 3 pin socket and use speedfan as siumatfung suggests.
cheers all !

theese are the ones im using here.

http://www.sharkoon.com/html/produkte/luefter/silent_eagle_se/index_en.html

Though i cant menion where i purchased them from, due to forum rules regarding competitiors.

ecat · 6 May 2009 at 10:01

Louis_Y said:
ecat - what model of Asus mobo do you have? I have a feeling that the older ones probably support voltage regulation of the CPU fan according to CPU temp, but they've removed it from the newer models

M3A79T-Deluxe. The easy test is to enable Q-Fan in the bios, fan speed should change during boot/while on load and it saves messing around with SpeedFan

PaulyD said:
steveinspain - I used a different guide before but found this one quickly which will do the job, was a right pain in the **** when I did it!

http://www.addictivetips.com/window...-and-change-the-temperature-of-your-computer/

iirc the final screen shot in the above link is the only one you need to test SpeedFan/mb/3pin/4pin control. Set all the PWM/Fan modes to 'Manual Control' and you should be able to change the speeds from the SpeedFan main window (100%^V).

A side note here, when messing with SpeedFan control then returning to 'Smart Guardian", ie MB control on my system, it sometimes (always?) requires a reboot before control is re-established.