Desktop display slow down in Linux Mint 11 64-bit
 

After using my PC for a random amount of time, the display refresh drops dramatically. Dragging windows and Compiz effects go from perfectly smooth to very jerky, as does video playback of any kind and I find both OpenGL screensavers and my own OpenGL apps also run very slowly.

If I switch the window manager to Metacity, the desktop and video responsiveness goes back to normal, but OpenGL performance does not. If I log out and log back in, display refresh goes back to normally smooth - but will degrade again after some time.

This happens for me with both 8800GTS and GTX580 cards, and on driver versions 285.0509 and 290.10.

Attached is an nvidia-bug-report log.