Hi Sebastien, I've opened a bug there, but I focused more on performance profiling. I'll expand on it and explain the problem in detail (I had just linked to launchpad).
Here it is: https://bugs.freedesktop.org/show_bug.cgi?id=10173 -- Sluggish rendering since xorg 7.2 update https://launchpad.net/bugs/88815 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
