launching multiple project files on 1 PC get framedrop

Hi, I’m trying to run 3 different project files on 1 computer.

my goal is to receive interaction through arduino and play game. Because of serial communications, I divided the project into 3 project files. Individually running.

It does work well, but if I switch to other game with alt+tab or window+mouseClick, the rest 2 gets a bit of a frame drop. I don’t know if this is the windows10 issue…

So I was wondering how can I prevent frame drop while running 3 games on fullscreenmode(it doesnt have to be Fullscreen mode in unreal, it only needs to hide other UI like windows task bar.