Re: Random crashes, NVRM Xid messages
There is a rather involved way to force a NVRM: Xid and partial desktop freeze on an otherwise stable KDE4, by exploiting a nasty bug in nedit with ARGB visuals.
In every case, I was able to revive the desktop by toggling composite off-on, using the KDE4 hotkey (Alt-Shift-F12). I suspect there is a way to perform a similar toggle in Gnome.
CentOS 6 + KDE 4
GeForce GTS 450