This isn't too surprising. XGL doesn't currently sync screen updates to vertical redraws so it is quite possible that you might get tearing if things aren't being redrawn extremely quickly. Another alternative explanation is that there is a bug within the nvidia binary drivers but either way I don't think this is going to be a high priority bug...
-- Using anti-aliasing causes flickering (nvidia i386) https://launchpad.net/bugs/38122 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
