fullscreen fps drops

When I'm in fullscreen mode on a YouTube video (1920x1080), it starts lagging, but when I'm pressing Alt+Tab and switch to another window (ex. Task Manager), the lag stops, and the quality remains the same. Better understanding in this video: View: https://www.youtube.com/watch?v=nI3Rf0Mv-Ik...

i just got a new pc Windows 10 laptop and games are capped at 60 fps. after going through everything i found out the problem was fullscreen optimization. i remember having the same issue with my old pc but i was able to fix it without disabling fullscreen optimization (which would mess with...

I left for a trip to my hometown for 2 months and then came back to see that whenever I tried to play games in fullscreen, I would drop to around 2-4 frames and my second monitor was flashing black and also dropped to the same framerate. I tried wiping my computer but that didn't seem to fix the...