I've lately been having an issue with a couple of games and my monitor. I'm not sure what the problem is exactly, but the game will be set in Fullscreen at my monitor native resolution 1920x1080, yet sometimes the game doesn't display full screen. Sometimes it has black borders around the edges, not just the sides, but the whole thing, and the image inside is a bit blurry.
So far it's done this with Stalker Call of Pripyat and Lord of the Rings online, both while running in DX10 mode.
I have an ATI 4890 with updated drivers and an Asus VH242 monitor hooked up HDMI through my vid card.
It displays normally when I put it in windowed mode, but fullscreen is messed.