I've been reading about the upcoming merom processor with some interest. I suspect, 25seconds after my core duo mini is out of warranty, it'll be on its back, in pieces getting a new brain. But that got me thinking (oh dear - always dangerous). The Merom and its family of CPUs are 64 bit. OS X on PPC is also 64 Bit. But I bet the OS X that's installed on my mini now is 32-bit So what happens when I open my baby, replace her 32bit brain with a 64 bit brain. Howz the OS gonna behave? Will I need to reinstall to get full 64 bit functionality? Any ideas?