CPU FAN1 always running at full power

[RikkIV]

I just installed a new CPU fan 'Cooler Master SickleFlow 120' on my Scythe Mugen Rev.B combined with my MSI Z170A motherboard. And that fan seems to be always running at 100% (2000+-RPM). No matter what I do in the BIOS or MSI command center and it doesn't change a thing even the graph doesn't show the correct data:

Using 'smart mode', fan tune or manual mode doesn't do anything. Also CPU temperatures are normal at idle 20-30 degrees celsius. My other CPU fan(2) is doing what its supposed to and it running a low rpm when idle and I can modify that RPM.

I have no clue what is causing this how can I change/fix this?

 

[getochkn]

is it a 3 pin fan or 4 pin fan and is the fan header on the motherboard 3 pin or 4 pin.

 

[RikkIV]

is it a 3 pin fan or 4 pin fan and is the fan header on the motherboard 3 pin or 4 pin.

I believe the fan is 3 pin and the motherboard is a 4 pin.

 

[getochkn]

sometimes the bios lets you tell if you have a 3pin or 4pin.

See 3 pin works like this. 1 pin is ground, 2 gives RPM speed, 3 varies voltage from 5v to 12v to control the speed.
4 pin works like this. 1 pin is ground, 2 gives RPM speed, 3 gives a constant 12v, and 4 sends a PWM (pulse width modulation) signal which is usually a very low <1v pulse that tells the fan how fast to spin.

SO, if you have a 3pin on a 4pin, it will get 12v all the time and, thus, spin at full speed. Either need a 4pin or to tell your motherboard, if possible, that you have a 3pin.

 

[RikkIV]

sometimes the bios lets you tell if you have a 3pin or 4pin.

See 3 pin works like this. 1 pin is ground, 2 gives RPM speed, 3 varies voltage from 5v to 12v to control the speed.
4 pin works like this. 1 pin is ground, 2 gives RPM speed, 3 gives a constant 12v, and 4 sends a PWM (pulse width modulation) signal which is usually a very low <1v pulse that tells the fan how fast to spin.

SO, if you have a 3pin on a 4pin, it will get 12v all the time and, thus, spin at full speed. Either need a 4pin or to tell your motherboard, if possible, that you have a 3pin.

That actually sounds really logically..... I am still confused about the difference between PWM-fans en non-PWM-fans. I know this fan in particular isn't PWM. Do CPU fans need to be PWM to be working properly? I believe PWM fans are always 4 pin so it would work naturally. Also PWM-fans seem to be more expensive and less powerful what fans sort of fans do I buy here, I need buy new cooler fan clips anyway so might as well buy a new fan.

 

[getochkn]

I explained the difference. One fan the speed is controlled by voltage, the other has a constant voltage and the speed is controlled by a signal. They only need to be PWM if your motherboard doesn't let you switch it in the BIOS to tell it that it's a 3 or 4 pin fan or can't detect it. My BIOS lets me say if it's 3 pin or 4 so it knows how to control it.