My CPU fans speed up when enter the play mode

I observed this issue in 2020 and 2021 but not in 2019.
I'm using two render textures(2560x2560) to show views of two cameras on the main camera.
The fans start to be crazy exactly the moment I enter the play mode and cool down immediately when I leave it.
Also, if I open the menu of Editor in play mode the fans cool down.
I don't think this is about CPU temperature, it makes no sense that I can cool my CPU in like 0.1second by opening a menu.

I loved 2020.3 LTS, but now I have to return to 2019.4 because it's horrible when you don't know what the hell an application is doing to your CPU fans.

I really think Unity should do something with their poor... "quality control" rather than making all the meaningless "updates".

 

i think one solution was enabling VBlank from quality settings. (at least for builds i had similar issue)

 

Thank you for the reply. Vblank is enabled already on my project.