New imac is running sweet. However, I see the pinwheel at times when I never do on my 13" MacBook Pro. I see it in two instances. First, when accessing the screen saver settings in system preferences. I do have over 9,000 photos and have the screen saver set to shuffle. Maybe that's the issue? I also see the pinwheel when waking up the computer from sleep. It could be the LED screen lights up so quickly now, the processor has to catch up? I have not done a reinstall of 10.6.2 and have installed Parallels and Windows 7. Anybody else having similar symptoms?