High X memory bugs are almost always caused by a runaway client program. There's nothing in any of the files you attached to suggest it is really an X bug.
You seem to have a number of non-standard software installed like virtualbox and chrome. Do a bit more analysis into what applications are running when this bug happens and try killing them off one by one. ** Changed in: xorg (Ubuntu) Importance: Undecided => Low ** Changed in: xorg (Ubuntu) Status: New => Incomplete -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/780424 Title: Xorg unresponsive after screensaver unlock with Dual Head To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/xorg/+bug/780424/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs