Comment 9 for bug 404331

Thanks for that, but it looks like whatever improvements have been made in the PPA, they don't affect this bug (or the new bug 421842).

I hadn't actually reinstalled the OS or run a live CD since reporting this, just upgraded using Update Manager. The Karmic live CD (alpha-4) seems to cause none of these problems: the most likely differences I can think of are that I have ndisgtk (with a Broadcom 43xx/Linksys PCI card) on the version installed on the hard drive; I had installed and uninstalled the proprietary RealPlayer; or the memory usage is different (I've run memtest86+ for a few hours with no errors). DRI and Compiz is enabled when running the Live CD, there is no xorg.conf to edit that I can see, but scrolling in Firefox is very slow. At least it rules out a simple hardware fault; I can't see how this could be down to a corrupt binary, since each package has probably been freshly downloaded since first reporting this bug, and it must be something in the configuration. I'll attach files from the Live and installed versions for comparison.

DRI-only issues mentioned in bug 421842 include segfaults and screen corruption on the window losing focus.