The fan header is damaged.
The fan header is damaged.
Hey, I noticed your MSI B450 Mortar Max isn't working properly with the "sys_fan3" header. The fan you received is an NF-A12x25 PWM 120mm model, and you're using the Noctua extension cable that came with it. It seems to function roughly half the time during boot, even though the motherboard checks the fan status. In BIOS it doesn't spin at all when it should (around 50/50). Sometimes it starts spinning when you boot into Windows 10 or when logging in, but not when you're logged out. The PWM mode is enabled with "smart fan" turned on, and sometimes it spins at 60% despite the temperature readings. If someone has any suggestions or findings, I'd really appreciate it!
Turn off quick-start settings in the BIOS. Keep in mind that many Noctua fans cease rotating once they hit their lowest RPM or PWM percentage—this is intentional.