because i went through 4, i thought i would pass along my purchase experience with the "new" early 2008, macbook version 4.1. first off, FUTURE SHOP HANDLED THIS ALL EXTREMELY WELL all temps etc are approximate(istat), i am not a pro. heat sink temps followed the core temps, other then when the airport cards ran hotter, and raised them. Celsius. macbook 1, 3.1 way cooler there my 1.1, blue screens aplenty, randomly closing all apps, no questions asked. black box freeze. Garage band extremely slow to load(30 sec+),sys prefs. pause on open, general hesitations within system.(NOT ENOUGH RAM FOR LEOPARD) temps: cores 30-50, ram 25, airport card, 40 idle, 50 hot. bottom 25 exchanged with 4.1, which they only had in stock, one week later. no restocking fee, 50$ refund macbook 2, 4.1 defiantly cooler from here under the shift key than the 3.1 leopard is fast again, no hesitations with the 2g of ram. garage band opens in 5-10sec. temps: cores 35-60, ram 40, airport card, 55-70, bottom 25 morning after purchase, the screen was gone . not cracked, ive seen that before, just black. no questions, no fee. macbook 3, 4.1 defective "k" on keyboard. it was there, but barley. this machine though, ran the best by far. temps: cores 25-35, airport, 42 idle, maybe 50 hot, bottom, 15. replaced, no questions macbook 4, 4.1(still) temps, cores 60-70, airport 60 at idle, runs great, hotter inside then any of them, still keeps cool on the bottom though. it seems there is alot of variability with the airport card temp, from idle at 40 to idle at 55+++. obviously the core temps are affecting the airport or/and vice versa, but this is a lot of variation for computer parts(layman opinion). The 4.1 is considerably faster loading GB, and has not blue screened yet like the 3.1(ram issue) I have never seen a man shut all your open apps to a blue screen, or freeze and ask you to please force the power off, because it cant do it itself. Otherwise leopard Aqua is very impressive, and now the other part is certified unix, which i find impressive. Moral of the story, leopard needs more then a g of ram to run reliably. the 3.1 processors are just as fast as the 4.1, but screwed without ram in leopard. Battery time is similar leaning towards the penryn. Wireless card variability, and even processor temps seem to be a random phenomena. if you are considering an exchange, this might affect your decision. cooler must be better right? (i.e.keep the one you have if it runs cool)?