UPDATE:
Upgrading to 2.6.30rc2 did NOT solve this issue.
david@ubuntu-laptop:~$ glxgears 1386 frames in 5.0 seconds = 277.199 FPS 1406 frames in 5.0 seconds = 281.172 FPS 1375 frames in 5.0 seconds = 274.887 FPS 1419 frames in 5.0 seconds = 283.761 FPS 1405 frames in 5.0 seconds = 280.881 FPS
david@ubuntu-laptop:~$ uname -a Linux ubuntu-laptop 2.6.30-020630rc2-generic #020630rc2 SMP Wed Apr 15 14:00:27 UTC 2009 i686 GNU/Linux
UPDATE:
Upgrading to 2.6.30rc2 did NOT solve this issue.
david@ubuntu- laptop: ~$ glxgears
1386 frames in 5.0 seconds = 277.199 FPS
1406 frames in 5.0 seconds = 281.172 FPS
1375 frames in 5.0 seconds = 274.887 FPS
1419 frames in 5.0 seconds = 283.761 FPS
1405 frames in 5.0 seconds = 280.881 FPS
david@ubuntu- laptop: ~$ uname -a 020630rc2- generic #020630rc2 SMP Wed Apr 15 14:00:27 UTC 2009 i686 GNU/Linux
Linux ubuntu-laptop 2.6.30-