When I move around in-game with fullscreen ON I feel like I am having 15 FPS but when I open F3 it goes is 60 and the lagg stops. I tryed to record it but when I start my recording software my FPS also returns to 60. It feels like my PC got hacked and someone is trolling me. What else would you think if your FPS gets to 15-20 only in fullscreen, when F3 is not open and there is no recording software running? Checked for viruses but couldn't find any so is is probably a bug.