Recently I've started having this weird graphics glitch on my Alum iMac. After playing wow for a few hours and some tabbing back and forth between game and browser the graphics will suddenly freak out and look like the attached pictures. When it happens if you change desktops or use Expose sometimes the graphics will look okay and then it'll freak out again. It's not just the game graphics that are messed up either, it's the entire desktop. The first time it happened was when the screensaver was on and i moved the mouse. I just restarted the computer and it didn't happen for a few days. Then after that it started happening atleast once every other day, sometimes twice a day. I have reset the PRAM as well and still have issues. I want to say its because of the last update because it's never happened before then, but I can't be sure. Anybody have some ideas?