Optiplex780, WinXP, ATI3400 - Corruption when dragging windows between dual monitors

I have yet to test this with a pc straight from Dell, but after imaging our computers with a fresh install of Windows XP Pro with SP3 our users can have issues when dragging any window between two monitors.  Each time the window is redrawn on the other monitor, it gets worse...eventually, if you drag back and forth over and over, the window will completely disappear.  Our users have become smart enough to minimize and expand the window by clicking in the taskbar but it's still an annoyance.

I've tried multiple versions of the Radeon drivers, including both the ones that shipped with the computers and the latest from ATI.  The issue seems to be related to a Windows power saving feature...I have one user that immediately disabled all screensavers, sleep mode, etc. and he says that he's never run into the problem.

Has anyone else seen something like this and found a solution?

Thanks,

-Brian