I managed to compile older versions of the radeon driver (e.g. 6.13.1), but the problem is still there, so it's most likely not caused by the driver. I am closing this bug.
** Changed in: xserver-xorg-video-ati (Ubuntu) Status: New => Invalid -- You received this bug notification because you are a member of Ubuntu-X, which is subscribed to xserver-xorg-video-ati in Ubuntu. https://bugs.launchpad.net/bugs/1062915 Title: Graphics slowdown with 12.04 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-video-ati/+bug/1062915/+subscriptions _______________________________________________ Mailing list: https://launchpad.net/~ubuntu-x-swat Post to : ubuntu-x-swat@lists.launchpad.net Unsubscribe : https://launchpad.net/~ubuntu-x-swat More help : https://help.launchpad.net/ListHelp