Weird 30 FPS Cap on Fullscreen mode

So today i decided to play some beam, and when i went on, it was noticeably slower. Like the main menu is laggy and delayed. When i get into the game and check the fps, its stuck at 30. So i tried clearing cache and went onto safe mode, and it still was capping at 30 fps. But then i changed it to windowed, and the fps went back to normal. I did the same with borderless, and it was normal. But when it was full screen, it dropped down to 30. So why is it doing that? I dont see that any difference between borderless and fullscreen, so why does the fps suddenly go down because of that? Yesterday nothing was out of the ordinary, so it was only when i tried playing today.
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awesome its fixed, thank you!