I have a strange issue with a dual monitor, extended desktop setup where the mouse is always fine on the primary monitor, but sometimes when I move to the secondary display the icon becomes garbled and distorted (sometimes it just looks like a vertical line, instead of a pointer). If I move the mouse back and forth rapidly between primary and secondary displays the level of "garbledness" of the icon will change and sometimes go away completely. If I switch the display settings and set it to "Duplicate Monitor 1" then I end up with a garbled icon on the primary display and an accurate one on the secondary. Very annoying.
Computer is Windows 7 Ultimate with an HD5780 and the newest video drivers. Monitors are two Dell 24" displays connected via DVI cables. I have also tried VGA cables.