Fan header broken?

Zelenia · September 3, 2020

Hey,

I got MSI B450 Mortar Max and for some reason one of the fans I got doesn't work as it should when connected to header called "sys_fan3". The fan I got is NF-A12x25 PWM 120mm and I've used Noctua's own extension cable that came with the fan.

It seems to be 50/50 if it starts to spin when the motherboard does the fan check when booting.The fan doesn't spin at all in BIOS even though it's supposed to (24% at 40C). The fan is in PWM mode with "smart fan" enabled. Sometimes the fan spins at 60% and ignores temperatures.

The fan seems to start spinning when booting into Win 10 or it spins when booting but stops when logged in.

I did check the header and it doesn't look like it's been bent. I did try this same header with 2nd fan without the extension cable and it still seemed to behave similarly with same issues.

If someone got any leads, I'd be grateful!

Stahlmann · September 3, 2020

Try disabling any fast-boot options in BIOS. Beware that most Noctua fans stop spinning after reaching their minimum RPM or PWM %. That's a feature.

Zelenia · September 3, 2020

7 minutes ago, Stahlmann98 said:

Try disabling any fast-boot options in BIOS. Beware that most Noctua fans stop spinning after reaching their minimum RPM or PWM %. That's a feature.

Aight, thanks. I didn't realize there is actually minimum speed for Noctua fans. I did check it up and it seems to be 20% for this model (around 450rpm)

I'll disable fast-boot options and see what happens.