The CPU is on the other side of the mobo? Ah, those nutty Apple engineers, what will they come up with next? What kind of heat sink do they put on it? Is there a fan down there too? Or do these mobos end up frying themselves in their own heat?

I know in an earlier version of this same computer, the CPU was mounted on a daughter board. Those machines were upgradeable. In the later revisions, though, they just soldered the CPU right on. I didn't know it was on the bottom of the mainboard, though. Not sure I would have thought of turning it over to look for the CPU either!