Noisy mac mini after updating to macOS Catalina?

Question

macOS

Updated a 2012 Mac Mini to macOS Catalina. And strange nonsense began to happen: when I actively work, there is no noise at all, even with an active load, but as soon as I move away from the poppy or put it into sleep mode, a wild noise begins. This was not the case with macOS Mojave.
Dropped smc, to no avail. I tried to find a process that loads the system - everything is within the normal range (CPU inactivity 92%).
Where should you dig? or reinstall Mojave...
UPD: Installed Catalina from scratch, the same effect (
UPD2: Rolled back to Mojave, restored from TimeMachine, everything started working ok, silence.

Answer 1

Try https://support.apple.com/ru-ru/HT201295 (call Apple)

The computer fans are spinning at a high speed even though the computer is not heavily loaded and is properly ventilated.