I have had a similar issue and executed the script creating the attached log file.
** Attachment added: "xorg bug script" http://librarian.launchpad.net/6583309/xorg100cpu.log -- Xorg uses 100% CPU https://launchpad.net/bugs/87351 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs