There are settings that affect CPU the most and settings that affect GPU the most. If you set everything to low you also set some CPU heavy settings to low which gives the game more resources to make the GPU reach higher FPS numbers which it will always try to.
Unless you set a maximum FPS you will always stress either the CPU, GPU or if your system is perfectly balanced for the game: both.
I am having this issue as well...which is insane sine i have an 8700k and Titan Xp...Please help this game is destroying my GPU - doesn't matter if i set the res all the way down and turn settings all the way down my gpu is at 100% all the time in task manager...
i think that, like fortnite, the game is just not optimized properly. even games like destiny 2 and black ops 4 dont take up 100% of my GPU usage. This could also be a possible reason for the multitude of crashes users get when playing the game.
