There have been other threads about this topic, but I'm sure some are still looking for a solution. I was one of the people who used the double update to go from 10.6.5 to 10.6.7, simply because I had just got my new MacBook Air and that was under the 'Software Update'. After going to 10.6.7, I noticed a huge loss in gaming performance, as did many others. So, I did the only thing I could do at that point in time. 1) Do a clean install of OS X to 10.6.5. 2) Download 10.6.6 from Apple (http://support.apple.com/kb/dl1343) After the update to 10.6.6 everything was working perfectly, until this morning I got the screen flickering issue and was forced to download 10.6.7. 3) Optional, but recommended: Backup your data via Time Machine. 4) Download 10.6.7 from Apple (http://support.apple.com/kb/dl1363) And there you have it. Instead of installing the double-update, simply download each update, individually. I am currently running 10.6.7 with StarCraft 2, Call of Duty 4, World of Warcraft, all playing perfectly. Thanks to others who posted this solution.