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3pin, 4pin, PWM, Voltage Control?

Classic_GOD
Level 10
Hi,

Firs of all I'm sorry if this was answered before but I can't find the clear answer for my question.

I'm planing to join the ROG family once the M6Impact becomes available and wanted to make sure what kind of fan speed regulation are the ROG boards capable of using for chassis fan headers. I know for that Asus uses new connector on the CPU Fan header to detect what kind of fan is connected but all the other 4-pin fan headers on the motherboard are just standard fan headers.

The only way to control both 3pin and 4pin fans (and I know they are capable of controlling both) without any detection is to use voltage regulation or have menu item to set the type of the fan. I didn't saw any 'fan type' setting on the UEFI screenshots for ROG boards and also didn't saw option like this in UEFI of my current ASUS board (P8H77-I).

So my question is:
Are the chassis fan headers on new ROG boards capable of controlling fans using PWM (and if so how you set them in PWM mode) or are they always voltage controlled.

The answer to this question will influence my choice of fans for my next build so I hope someone will be able to answer it 🙂
Thanks.
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20 REPLIES 20

Menthol
Level 14
I believe all fan headers are 4 pin PWN, you can set in bios several options on speed control for all headers, or speedfan with software, I believe it may only be the CPU fan header that can control a 3 pin fan properly

Raja
Level 13
Chassis fan headers control in DC mode only - and that will control 4 pin fans but not in PWM mode.

Raja@ASUS wrote:
Chassis fan headers control in DC mode only - and that will control 4 pin fans but not in PWM mode.
That was the answer I was looking for. Thanks! 🙂

[EDIT]
I know it's off-topic but if I can ask just one more related question 😉
Do the new ROG boards use real CPU core temps for fan control or like my P8H77-I cpu socket based temp sensor?

Classic_GOD wrote:
That was the answer I was looking for. Thanks! 🙂

[EDIT]
I know it's off-topic but if I can ask just one more related question 😉
Do the new ROG boards use real CPU core temps for fan control or like my P8H77-I cpu socket based temp sensor?


They use a combination of the on-die sensor and a socket-based sensor to produce a value that never matches other temperature readings.

Kwami wrote:
They use a combination of the on-die sensor and a socket-based sensor to produce a value that never matches other temperature readings.
Well, that's a little disappointing. Thanks for the answer 🙂

Classic_GOD wrote:
Well, that's a little disappointing. Thanks for the answer 🙂
Just use either Realtemp or Coretemp, they are pretty reliable.However in combination with fanspeed control, the temps from the mobo are used. And that gives sufficient cooling control.

Henkenator68NL wrote:
Just use either Realtemp or Coretemp, they are pretty reliable.However in combination with fanspeed control, the temps from the mobo are used. And that gives sufficient cooling control.
This is what I do right now. I create a log of real core temps and temps indicated by FanExpert and based on that I determine how to set my fans. 🙂

Raja@ASUS wrote:
Chassis fan headers control in DC mode only - and that will control 4 pin fans but not in PWM mode.


Does that mean 3-pin fans will be controlled through voltage? I read that doing so generates heat in the controller, how will the motherboard dissipate this heat?

I just ordered a Gene after a long indecisive struggle between the Gene and the ASRock Z87M OC Formula. Hope I made the right decision!

Superglu wrote:
Does that mean 3-pin fans will be controlled through voltage? I read that doing so generates heat in the controller, how will the motherboard dissipate this heat?
Yes, they will be controlled through voltage. Modern fans have very low current draw, the generated heat should be negligible.