It looks like Michal was correct in comment #7. One thing that might improve the performance of the open-source radeon drivers slightly in the latest upstream 3.0.18 kernel is this patch:
commit a674b8b3e345496a96aec389446650455b2fdfa1 Author: Alex Deucher Date: Tue Jan 3 09:48:38 2012 -0500 drm/radeon/kms: disable writeback on pre-R300 asics commit 28eebb703e28bc455ba704adb1026f76649b768c upstream. We often end up missing fences on older asics with writeback enabled which leads to delays in the userspace accel code, so just disable it by default on those asics. Reported-by: Helge Deller Reported-by: Dave Airlie Signed-off-by: Alex Deucher Signed-off-by: Dave Airlie Signed-off-by: Greg Kroah-Hartman -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/852554 Title: Poor video playback performance with radeon driver and compositing To manage notifications about this bug go to: https://bugs.launchpad.net/unity-2d/+bug/852554/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs