lately i learn that AMD drivers has a bug that makes memory clock of the GPU to work on full load even if the graphic card is on IDLE mode so if you have 2 or more monitors even if you dont play the memory clock is on full load i had to unplugged my 2nd monitor completely to go back at normal frequencies you can test it with GPUZ program at sensors tab and look for yourself https://i.imgur.com/51uKJuG.jpg
From googling it seems some people have luck 'just' ensuring their monitors are running at the same refresh rate. This includes going into the advanced display settings -> advanced adaptor settings -> monitor tab, and changing it to some other rate, apply, then back to your desired rate, and apply again. Through trial and error you may be able to work out which screen is changing and only have to change that to 'fix' it in future. If there's a mismatch between screens (which may not be reflected in the displayed refresh rates, hence changing each setting away and back above) the memory will run at full speed.
both my monitors runs at 75 hertz but still bug there but different resolution 1 LG 2560 ultra wide 29 inch 2.LG 1980 23 inch same refresh rate @75
