Hi, I'm considering upgrading my rather old iMac, but want to have a better sense of how much performance improvement I might expect if I do so, and am hoping to get some feedback. I have a fairly specific use case in mind. I am a typical dad with a bunch of family pictures in iPhoto (currently over 40k photos and growing). I use the Faces feature of iPhoto extensively and am getting frustrated by watching iPhoto beachball for 10min+ as it computes candidate faces. I can see through system monitor that both cores are pegged when iPhoto does this, so I think this computation scales with additional cores, and that this is CPU-bound rather than io-bound. So looking at multicore benchmarks like the one at: http://browser.primatelabs.com/mac-benchmarks I think that if I get a 3.2ghz i5 iMac I might expect a 4-5x speed up and a 3.5ghz i7 might get me 5-6x speed up, but would appreciate knowing if I'm thinking about this right, and any other suggestions or advice people may have. Thanks!