Apple has fixed a problem with the new 27″ iMacs regarding intermittent display flickering and occasional blackouts. This issue affects the new 27″ iMacs with a ATI Radeon HD 4670 or 4850 graphics card. I noticed this happening on my new iMac last week, I had a random white bar that would flicker on my screen, and once in a while my screen would turn black for a second or two. The update can be downloaded at your apple software update, or you can download it here