I know I'm crazy! I bought the $1999 i5 model to test running pro audio (90% of what this machine will do). On this machine I typically run about a 25% total CPU load. It has handled everything I have thrown at it. I even used this CPU stress test http://osxdaily.com/2012/10/02/stress-test-mac-cpu/ to put an artificial 50% extra load on the machine. No problem plus temps stayed under 70degC - no extra fan noise. So I ordered a BTO 3.5 i7. If I load two instances of the above test on each machine (=50% CPU for the i5 and =25% CPU for the i7) the i7 is running WAY hotter. The i7 CPU even got to 90degC and kicked the fan up to 1800rpm (no like). Although I could load much more on to the i7 the fans would be a total bummer (for me - many would't care). My first wonder is if the i7 BTO didn't get attached to the heat sink correctly. I mean the i7 and i5 die are the same size and for the same load I was assuming they would have very similar thermal performance. Maybe I'm wrong though First I will have to talk to Applecare - but unless there is something clearly wrong - and crazy as it is - I may just keep the i5 or BTO an i5 with an SSD. FWIW: My main use is low track count at the lowest latency I can do (currently 96kHz/64buffer). Loading up huge sessions is not really my game and in ProTools about 30% to 40% CPU usage on the i5 is as high as I can imagine going.