Question Windows overrides BIOS Manual Fan Speeds

Nov 19, 2019
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Hi, I just completed building my first PC and everything booted up completely fine however the fan speeds are running ridiculously high on windows boot generating a large amount of noise. When entering the BIOS the fan remains on very low speeds. I tried to manually change the speed of the fans in relationship to temps within the BIOS however it seems that windows overrides these changes and continues to run at high rpm almost instantly(at the password screen to sign in).

I have an ASUS Z390-A Prime motherboad and also the Noctua NH D15 cooler. I also have two case fans that came with my Phanteks Enthoo Pro. It is not just the Noctua D15 that is running at high speeds but also my case fans. I connected my Noctua NH D15 into a Y splitter then plugged that into "CPU Fan". The Phanteks Enthoo Pro came prebuilt with a PWM hub and I installed the 4pin into "CHA_FAN2". I'm pretty sure I mounted the cooler correctly. I'm unsure to why my fans suddenly run at such high speeds despite my attempt at changing them in the BIOS.

Thanks for reading, any advice would be highly greatful!
 

Lutfij

Titan
Moderator
Connect all fans to the PWM Fan hub, then have the Fan hub connected to the CPU_Fan header on the board. You should be able to have all fans run according to the CPU temps. That being said, which version of the BIOS are you on for your motherboard? Check and see if you have any updates pending. Speaking of updates, manually update/flash the BIOS.

Which version of Windows 10 are you on?

Just for the sake of relevance, include your specs like so:
CPU:
Motherboard:
Ram:
SSD/HDD:
GPU:
PSU:
Chassis:
OS:
 
Nov 19, 2019
2
0
10
0
Connect all fans to the PWM Fan hub, then have the Fan hub connected to the CPU_Fan header on the board. You should be able to have all fans run according to the CPU temps. That being said, which version of the BIOS are you on for your motherboard? Check and see if you have any updates pending. Speaking of updates, manually update/flash the BIOS.

Which version of Windows 10 are you on?

Just for the sake of relevance, include your specs like so:
CPU:
Motherboard:
Ram:
SSD/HDD:
GPU:
PSU:
Chassis:
OS:
Unfortunately there is no 4 pin connector on the PWM Hub, only the connection which is labelled as CPU_FAN that I connected to the motherboard(CHA_FAN). I have already updated the ASUS BIOS too.

I'm running on Windows 10 Home.

CPU: Intel 9700k 3.6 GHz
Motherboard: ASUS Z390-A Prime
RAM: Corsair Vengeance LPX 16 GB 3200MHz
SSD: 250GB Samsung 850 EVO
GPU: Gainward GTX 970
PSU: Corsair HX 850
Chassis: Phanteks Enthoo Pro
OS: Windows 10 Home

I installed ASUS Suite 3 to check Fan RPM. The CPU Fan is running at 225rpm(which is my Noctua D15). However it seems that my case fans that are connected to the PWM Hub is not detected as it does not show under CHA_FAN. I tried to plug both my front and back Phanteks 3 pin case fans seperately into CHA_FAN and it did show up then.

Does this mean that my PWM Hub 4pin is faulty? The case fans still run despite it not registering but they run at full speed on windows boot. Would it be possible for me to connect my two case fans directly to the Motherboard? I did some research and some people have made the suggestion to do so and switch to DC. However, I'm unsure of how to do this without screwing anything up.
 

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