[SOLVED] Asus C246M Pro Fan Control?

[Meru Otonashi]

Hey,

I just registered to check with other people that may have this professional grade motherboard:
I've installed a 3-pin Noctua fan into this system on FAN_FRNT3, and I'm noticing that in the motherboard, no matter what fan control speed I set, it simply runs at maximum...

There are no Q-Fan or any sort of configuration in the BIOS to set it to DC Mode or PWM mode... The only choices I have are Automatic, Max Speed, or Manual. On manual, even if I force the fans to 10% utilisation, it revs at full speed. SpeedFan does not help either. My only conclusion I can think of is that the fan headers on this board only accepts PWM 4-pin fans.

Am I correct to assume that?

Thanks a lot for your help!

 

[Karadjgne]

DC fans (even Noctua) require a certain low limit to spin, for the better fans that's 5v (40% duty cycle) for many its 7v (60%), so you'll not be able to set limits below that and expect the fan to spin. Since you did, with a 10% setting, and nothing happened, it'd be safe to assume 4pins =pwm.

PWM fans generally won't spin at less than @ 20% duty cycle, not enough amperage in the power requirements since pwm are constant 12v.

The fan on your cpu cooler is most likely (should be) pwm. You could temporarily swap them and test the theory.

 

[Meru Otonashi]

DC fans (even Noctua) require a certain low limit to spin, for the better fans that's 5v (40% duty cycle) for many its 7v (60%), so you'll not be able to set limits below that and expect the fan to spin. Since you did, with a 10% setting, and nothing happened, it'd be safe to assume 4pins =pwm.

PWM fans generally won't spin at less than @ 20% duty cycle, not enough amperage in the power requirements since pwm are constant 12v.

The fan on your cpu cooler is most likely (should be) pwm. You could temporarily swap them and test the theory.

Thanks. The manual has no sort of mention about this, and Asus support is currently down due to isolation of COVID, so I couldn't get any sort of vendor support.

Yes, the CPU fan is a 4-pin PWM header, and it seems to work.
Initially, my tower is using stock case fans, and the sound was never much of a bother because the rated speeds were 1000rpm on them, and it was never audible enough to hear.

Since, I needed an extra fan as hard disk temps were on the rise as it is getting warmer, thus I installed a new Noctua 140mm fan. Now my computer is running like a jet engine. Upon monitoring the BIOS settings, I noticed that all my stock fans are running at near full speed, so I went ahead and purchased new Noctua PWM fans. While waiting for those to arrive, I'd think to inquire about this here.

My CPU cooler is the NH-L9i, without the limiter installed, it's rated for 2500 RPM, but I recall during all this time validating in the bios, it was always running at around 1200 RPM, so the controls definitely work.

The reason I suspect this board only supports PWM fans was:

1. There is no DC Mode or PWM Mode option
2. Lowering the duty cycle to 10% (the minimum the board can handle) did not change anything for the case fans.

Thanks so much for taking the time to reply, I'll just patiently wait for the new fans to arrive and live with this jet engine for the time being.

 

[Karadjgne]

👍Ok then. No worries, 😁