This problem has been occurring ever since I got my MacBook Pro Retina 15" back from the Apple Store (fixing an issue with the screen, as far as I know, they didn't touch anything software wise). On both Safari and Chrome, when I watch a video in full screen, it stutter. It doesn't matter what GPU is running at that moment. Does anyone have any suggestions? Edit: And of course, I figured out a solution 5 minutes after posting this topic. I opened up the flash preferences, and deleted the local storage within the plug-in. As far as I can tell, the issue has been fixed. Edit Edit: Or not. Check third post.