How come I can run 64-bit Windows 7 on my first gen Mac Pro, but I can't run Snow Leopard as completely 64-bit (with the 64-bit kernel). What am I missing here? Is it truly a hardware limitation or is it just a software block that Apple has put on these machines? I always thought that you couldn't run Snow Leopard 64-bit Kernel because of the EFI32. After installing Windows 7 successfully, it makes me wonder if the inability of running full 64-bit Snow Leopard is just an artificial limitation. What's the deal? I could be completely wrong about all of this. I'm still confused about the EFI32 thing. Can someone shed some light on this? Thanks.