intressting, so may be a windows issue similar to the sound-driver chaos.
and this is why we mention heat-issues and in special in main menu.
Your GPU do what they can and this cause a very high load in main menu. Limit the fps is one first step to not get “1000fps”, but in special for users with 4K it doesnt helps at all. The background rendering cause a lot of gpu load, also with limitation of fps. Here is a huge topic in wishlist category about: Lower Resources in the Menu, Downloading, and Minimized. FPS cap?
Ah, and you dont need necessarly Afterburner for limit the fps, just open nvidia control center and you can set two different limits : max fps and max background fps ( window is not in focus ).