Comment 8 for bug 774414

I'm also experiencing this issue on AMD Bobcat (E-350) hardware using both the open source drivers and Catalyst 11.4 (both Ubuntu shipped and the official release). Running AMD64 version of Ubuntu 11.04 desktop, fresh installed. Happens in Unity, haven't tested classic session yet.

Something peculiar I've noticed is that running Quanta Plus makes the problem much worse. This is true for my Bobcat laptop, and my desktop machine (Phenom II X4 955, nVidia GTX260, binary driver supplied with Ubuntu 11.04). As soon as Quanta Plus is quit, window movement improves significantly. Perhaps an incompatibility as such between KDE3 and Compiz? Like David mentioned, it's almost like there's a flood of events between various processes leading to the stalls/slow down..