I just got a new ATI 5850, and when I use it at my monitor's native 1920x1200 resolution or 1680x1050 resolution it works fine, but when I try to go lower than that it has thick black bars at the top and bottom of the screen. I tried 1440x900 and 1280x800 and it happens to both of them. The black bars are very thick and take up pretty much half the screen together. Sometimes I like lower resolutions so everything isn't so small when browsing.
I just updated to the newest drivers and also tried setting the resolution through the CCC with no luck. Any ideas?