[SOLVED] PWM CPU Fan always running on full speed

Feb 17, 2019
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Hi, I've noticed that my CPU fan runs at full speed all the time even though the CPU is barely used by the system (usually at 15-30% of usage) and is at around 30°C (85°F).

My setup:

MB: Asus Z170i Pro Gaming (BIOS version: 3406, 2017/07/21)
CPU: i7-6700
CPU Fan: Noctua NH-D14
RAM: 32GB (G-SKILL Trident Z 2*16GB DDR4 3200MHz CL14)

The CPU fan is plugged into the CPU fan slot which according to the user manual (https://dlcdnets.asus.com/pub/ASUS/mb/LGA1151/Z170I_PRO_GAMING/E10725_Z170I-PRO_GAMING_UM_WEB.pdf, page 1-16) should be PWM enabled.
The CPU fan setting is set to Silent PWM mode, however no matter what I do in the BIOS setting, it always runs at around 1250RPM (which is almost the full speed of the fan).
 

Achaios

Honorable
BANNED
May 28, 2013
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Yeah well, ASUS boards have got two CPU FAN ports, one to the right and one to the left at least on my VI Hero.

Solution is ez, plug the cpu fan to the other cpu fan port. If I recall, it's called CPU OPT.

The one you have it currently plugged in always runs the cpu fan at 100% speed. I had read the reason at some point in the past but I forgot it bc as I recall it was meant for smt that I didn't use.
 

Achaios

Honorable
BANNED
May 28, 2013
225
23
10,695
18
Yeah well, ASUS boards have got two CPU FAN ports, one to the right and one to the left at least on my VI Hero.

Solution is ez, plug the cpu fan to the other cpu fan port. If I recall, it's called CPU OPT.

The one you have it currently plugged in always runs the cpu fan at 100% speed. I had read the reason at some point in the past but I forgot it bc as I recall it was meant for smt that I didn't use.
 

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