Based on the standard configurations, how will the 21.5" with the Radeon 5670 perform vs the 27" imac with Radeon 5750? Sure, the 27" has a better graphics chipset, however it has more than 35% more pixels to run. Games that will be played are Starcraft2 and Fallout 3. If i buy a 27" one, I do sure want to play stuff at the resolution it's designed for. So, whats best?