Hopefully this fixes some of those issues we've been hearing about on 27-inch iMacs. The firmware update, or specifically the issue it fixes, might have been resposible for Apple's delaying the the delivery for the larger iMacs to after Christmas. According to Apple, the 683K file "updates the graphics firmware on ATI Radeon HD 4670 and 4850 graphics cards to address issues that may cause image corruption or display flickering." What do you think?