Comment 1 for bug 98783

Using Kubuntu Gutsy on amd64, nvidia-glx-new package, 512MB RAM

It seems that firefox/flash is indeed the culprit. I've been trying to track down the cause of unresponsiveness in my system for days. First I figured it was Xgl, so I disabled it - but then the bug hit me again on plain Xorg. Finally found this bug report. Closed firefox, found that it left orphaned processes. Killed those off, now my system seems as responsive as ever. I am using a 32-bit browser in a chroot environment, if that helps.