I have two 4850s, three monitors, and am running the most recent CCC and Windows 7 64bit. I've been having a problem for a few months (across multiple versions of CCC) where the borders around windows (the transparent part) will flicker occasionally. During the flicker the transparent portion of the window will alternate between transparent and opaque. This also happens in Photoshop CS5 where except it flickers between the CS5 window and a generic windows 7 (opaque) border. It does not happen in Microsoft office however. I've already tried uninstalling and reinstalling CCC but it doesn't seem to help.
Also I can have a bit of lag when moving windows between monitors.