Easiest way is to make backup of applegraphicspowermanagement.kext or just rename it to applegraphicspowermanagement.kext.bak and then rebuild you cache with app like Kext Utility.
Only drawback I see is that graphics card will now use native power management and not Mac OS one. One thing I've noticed, applegraphicspowermanagement.kext has list of graphics cards, so if your card is not identified it appears that generic power / sleep states are being used thus producing glitches.
A bit more about power / sleep states. You've probably noticed that when you have certain animation first time in OS X, it is choppy, but second and third time it's animated perfectly. That's where applegraphicspowermanagement.kext is messing up the states. You can try it on Launchpad or Mission Control animations.
Here's more info on the issue, it's for nvidias but it applies to every graphics cards although ATI is generally more supported on OS X.
http://www.rampagedev.com/?page_id=311
http://www.insanelymac.com/forum/topic/266036-guide-edit-app...
More about kext itself; it contains the list of supported graphics cards (poor one) and power states for them. Some states are badly done even with supported graphics cards. I had a lot fun with this kext back in the ole' days after Intel switch.