The reason for that appears to be that there is a lack of a proper upper limit for the game’s GPU usage while in the main menu.
Please add a limit to it. I don’t need 1000 FPS for the main menu.
You need to cap your framerate or enable vsync. Your GPU is trying to render hundreds of frames every second since no limit is set. This behavior is normal for most games, only a few place a strict upper limit.