I'm seeing an average FPS of 125 in Windowed mode, but when I go into Full Screen mode my FPS shoots up to 850.
I guess this is normal?
Maybe this is expected, maybe not. I think it probably makes sense because the OS is working overtime in Windowed mode. I just want to make sure though.
Yes, perfectly normal. In Windowed mode the window shares the use of the graphics card with any other stuff that might be going on. In fullscreen mode the OS can just forget about dealing with any other graphics (generally) and can give you more exclusive access to the card more of the time.
Cas :)