MSI z170a pro can't control the CPU fan speed

[Vld01]

Hello! So, my problem is the following:I can't control the cpu fan speed no matter what I try - it's stuck at around 1700rpm (max for this fan should be around 2000rpm) and it's pretty loud. Cpu temps range from 25C idle to 35-40 in load
Mobo:MSI z170a pro and cpu fan: cooler master 212x
The weird thing is that I can control the speed of the 2 case fans (3 pin connectors pluged in 3 pin fan headers on the mobo)
Things i tried and have not worked:
-control fan speed from the msi command center - manual/ smart fan; no matter what option I choose the fan speed remains constant
-try out all windows power plans and with each one trying to change the fan speed from the msi command center
-connect the 4 pin cpu fan to both mobo 4 pin connectors (CPUFAN1 and CPUFAN2)
-CMOS clear
-switch with a case fan:
cpu fan 4pin -> 3pin header case fan AND
case fan 3pin -> 4pin cpu header;
Now the case fan that's seen by the mobo as a cpu fan is stuck at around 1400rpm and again I cannot change that in bios/msi command center be it manual or smart fan control
It seems to me that the 4pin connectors on the mobo are bugged in some way be it hardware or software.
Any ideas on how I can fix this? thanks in advance
Build:
mobo: MSI z170a pro
cpu: intel 6600k
cpu cooler: cooler master 212x
windows 8.1 64
bios version: 1.80

 

[weberdarren97]

Many newer boards do not allow exclusive software control of the CPU fans. That's likely what's going on here.

However, 35-40C in load is great. Why do you want to slow it down?

 

[Vld01]

Many newer boards do not allow exclusive software control of the CPU fans. That's likely what's going on here.

However, 35-40C in load is great. Why do you want to slow it down?

1. The pc is a little loud this way - but this is a minor inconvenience
2. I believed that the cpu fan should adjust it's speed in order to maintain optimal temp values - if I overclock in the future I'll have a bad time with this constant speed

 

[weberdarren97]

You're good until about 85C.

Seeing as you're at 35-40C load at default speed, you'll likely reach power delivery limitations before you reach thermal limits.