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Prime Z690-P CPU Fan speed not working correctly

plee5509
Level 7
I have a Prime Z690-P and all setup working perfectly with Windows 11, but noticed an oddity with the CPU Fan. I'm using a CoolerMaster EVO V2 but the same happened with the Intel stock cooler.

Basically the speed goes in reverse, by that I mean as the CPU temperature increases, the fan speed of the CPU cooler slows down and hits the minimum setting, as the CPU cools down, the fan speeds up. If you think about a dot on the Q-FAN chart for the temperature, it moves in the wrong direction. All other fans work correctly. Also when in the BIOS and in the Q-FAN settings, if I adjust the chart the fan works normally, for example set turbo mode, the fan speeds up, select quiet mode the fan slows down. It just seems that the temperature change moves the speed in the opposite direction that it should. I've tried DC Mode and PWM Mode, in DC Mode I set the fan to stop at it's lowest setting, and sure enough, run a benchmark to stress the CPU the fan slow downs and stops, stop the benchmark and see the CPU temperature fall, the fan starts back up again! I've ran several Q-Fan calibration tests and it's made no difference, the CPU fan always behaves in the opposite manner it should with temperature. Obviously this isn't good! I've done a full reset of the BIOS and it made no difference.

I downloaded some fan control software to run in Windows and configured it for the CPU fan, and this works it perfectly, and so points the finger at a bug in Q-FAN firmware/BIOS.

Posting here in the hope it gets picked up by Asus, or if anyone has any ideas how I might fix it as I'd rather not run software to control the fan.
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22 REPLIES 22

STARRAIN_ROG
Customer Service Agent
Hi plee5509,
Our tech team has tested the motherboard and devices at hand, but cannot reproduce the issue you mentioned. CPU fan speeded up when the temperature increased and it slowed down when the temperature decreased in PWM mode.
Please follow the instructions in the following link to clear the data by using CLRTC Pin and reinstall the mercury battery on the motherboard to check if the issue still present.
https://www.asus.com/support/FAQ/1040820/
If the issue still occurs, please send the motherboard to our RMA for further examination.
Thank you.

STARRAIN@ROG wrote:
Hi plee5509,
Our tech team has tested the motherboard and devices at hand, but cannot reproduce the issue you mentioned. CPU fan speeded up when the temperature increased and it slowed down when the temperature decreased in PWM mode.
Please follow the instructions in the following link to clear the data by using CLRTC Pin and reinstall the mercury battery on the motherboard to check if the issue still present.
https://www.asus.com/support/FAQ/1040820/
If the issue still occurs, please send the motherboard to our RMA for further examination.
Thank you.


Thank you for letting me know the outcome of their testing. Were they testing the BIOS operation, i.e. they had a system without Asus software on?

I will try the reset again when the next BIOS is released, as I'm now able to working around the problem by moving the fan to the pump header (which works correctly), I'm not in too much of a hurry to experiment or RMA the board. It can't be hardware fault if software within windows works the CPU fan correctly, if something was physically wired wrong, the same thing would happen under software control.

STARRAIN_ROG
Customer Service Agent
Hi plee5509,
Our tech team had a system with a bench test to raise the CPU temperature and use software to monitor fan speed without Asus software on.
Thank you.