I used to be an field engineer for fujitsu fixing gateway, compaq, etc (albiet five years ago) and they all automatically detected processor clock speed, etc. The Core 2 Duos run cooler than the previous models, but the architecture may or may not support 64-bit memory access. That was my question. If it worked in 64-bit, there should be a 50% increase in speed and would work with the 64-bit functionality in Leopard. OSX wouldn't detect it as a core two duo at the moment, but in light of the new imacs running core 2 duos an update should take care of that.
I could, of course, be talking nonsense!