I played with the 3.2ghz i3 in the apple store last week and aperture 3 ran as smooth as silk during my ten minutes of so of testing, I couldn't get it to slowdown. Now admittedly it was only a small library but the pictures seemed to have large file sizes. I've seen many people say that their core 2 duos struggle with aperture, so im not sure if the new 'i' range processors are having a big impact, whether the graphics cards are having an affect or if people with the problems are suffering from fragmented library's instead of their hardware. I think however that you will be fine with any of the 2010 imacs.