https://bugs.freedesktop.org/show_bug.cgi?id=71134
--- Comment #6 from Tom neatnoise@gmail.com --- Update
After updating packages to the latest versions (kernel to 3.12.0-next-20131111) gpu lockups and dramatic slow downs seem to be resolved.
I've uploaded 2 videos which describe existing problems.
pixel offset on diagonal (which appears to be in opengl apps too): http://youtu.be/jTnI446eD-Q
dpm issue: http://youtu.be/52ZlliTfqYI