I am starting to get weird video issues on my new 27″ iMac. It’s the Core2Duo model, not the i5 so I don’t believe it’s a processor issue. Mine has the ATI Radeon 4670 in it. Currently, the only was to fix it when the screen goes bonkers is to reboot or wait long enough and it will fix itself. I’ll report back with what Apple does to fix this problem.