I am also experiencing screen atrifacts with xorg-edgers:
Linux xxxxxx 3.5.0-5-generic #5-Ubuntu SMP Wed Jul 18 07:35:23 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux
xserver-xorg-video-intel 2:2.20.2+git20120731.fd3a1236-0ubuntu0sarvatt~precise
I am also experiencing screen atrifacts with xorg-edgers:
Linux xxxxxx 3.5.0-5-generic #5-Ubuntu SMP Wed Jul 18 07:35:23 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux
xserver- xorg-video- intel 2:2.20. 2+git20120731. fd3a1236- 0ubuntu0sarvatt ~precise