CPU fans stopped spinning

[Retcast]

This has happened in the past, and today it happened again: CPU fans won't spin unless I specifically tell them to through ASUS' AI Suite 3. The fans work perfectly, which makes me think it's a MOBO issu but I'm not sure.

 

[CountMike]

Which MB ? Asus ROG Hero 6 for instance have problems like that with latest BIOS. Asus AI Suite is also partially to blame, try setting fan curve directly in the BIOS

 

[7664stefan]

What might also be a potential reason is the min CPU fan RPM defined in the BIOS. I was experiencing the same with PWM fans on Asus Boards in the past.
Thus my question: what is the CPU load situation and temp when you notice that the fan(s) stop spinning?
Please add all other available HW including CPU and cooler.