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CPU fan won't slow down but does speed up

Level 7
Hi All,

Tried searching the forum and a lot of Googling but can't find anything specific to my problem or setup.

Basically, on booting up, my CPU fan is at low RPM as expected as the CPU is not being taxed. If I tax the CPU a little the RPM increases and the decreases as the load lightens on the CPU. However, if I start a game or anything that may make the CPU work fairly hard the RPM on the fan goes high but once the load is gone on the CPU the fan doesnt slow back down again. I have left it for a couple of hours and still high RPM. Interestingly, HWMonitor shows low temps as expected for no load but approx 600 RPM for the fan even though it's clearly spinning faster. If I reboot the fan goes back to normal.

I have i7 7700K, IX Hero mobo, 8Pack 16GB Ram, Phanteks PH-TC14PE_BK Cooler. No OC and in BIOS I have tried all on default and tried PWM for every fan setting there is (ie EXternal, Internal etc.) all set on Silent. For the CPU fan I have tried standard and manual (slight tweak from standard). All PWM.

Any help appreciated, pulling my hair out over this one. Any more info required please let me know.

Thanks guys.

Level 15

Chino wrote:
Try setting up a custom fan profile in the BIOS instead of using the Auto value.

Hi Chino and thanks for the response as well as an apology for my late reply. I bought the board and it came with BIOS from 2016 (09xx I think). I updated to latest and so far I think its working better now.

Thanks so much for offering a solution though.


Thought resolved but doing it again. When using the PC normally the fan speeds increase and decrease as expected with load and temps. However, if I go into a game (in this instance, Rise of the Tomb Raider) the CPU fan heads up to full speed. After quitting the game it remains at full speed. This is despite the fact that the temps on the CPU are all hovering around 30C and according to HWMonitor the fans are at around 560 rpm even though clearly going at full tilt. Ive tried setting custom as well as standard profiles all with the same result, the CPU fan speeds up and slows down as it should until in game when it revs up to max and then stays there.

Total head scrtatcher.

Wasn't even the CPU fan it was the GPU. Switched slots for the GPU and all fine. Hopefully some mod will delete this post before I make myself look any more like an amateur. 😞