FPS locked in Fullscreen mode (75 fps) but get regular fps when i drag it as a window (window mode)

[Zambe]

Yo I was wondering I have a problem with my pc and I don’t really know why so basically my FPS is stuck on 75 (because of my monitor) even do my vsync is off In both ingame and control panel it won’t go above 75 and this only happens when I’m in full screen mode and if I want to play ex: Fortnite, i need to have window mode and then it dosent get windowed mode so i need to like drag it to make one and then i get like 240 fps or whatever but wit a lot of input delay. (i have vsync off both in control pannel and in-game)