I had the exact same problem. I solved it by going in to Compiz settings and then OpenGL (under the General section) and disabling Sync to VBlank.
-- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/758980 Title: compiz very jittery on fglrx (r600) -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
