Fan Speeds of Whatsminer M21S Jumped by 2k

Hey everyone, has anyone dealt with the fan speeds on the Whatsminer M21S? I've been running mine in low power mode for around 9 months without any problems, and the auto fan speeds used to sit around 4500 RPM. But lately, for the past month, they’ve been consistently at 6200 RPM. The environment hasn’t changed, and the ambient and board temperatures are still around 55, 59, and 64 degrees Celsius. I checked the fans, and there’s nothing blocking the intake or exhaust, plus I’ve restarted the unit. After the usual 5-minute startup, the fans gradually ramp up to about 6200 RPM and just stay there. Anyone got any ideas?

I wonder if you solved this problem later? Normally, Whatsminer's M21S fan can up to about 7000 RPM, so 6200 RPM is not too high. It may be that the voltage or current of your power supply has changed at that time, so the speed has increased. If you want to keep it at 4500 RPM, I think you can choose to replace the lower-performance fan or use a voltage regulator.