Perhaps you're thinking of the 64bit version or windows microsoft made for intel's original 64 bit processor which had to emulate 32-bit. It had to because Intel's Itanium processors have no native compatibility with the x86 instruction set.
This version is for AMD's 64-bit line which is fully compatible with the 32-bit x86 instruciton set. I see no reason why Microsoft would choose to implement 32-bit support via emulation on a processor that can already run 32-bit software nativly. Of coarse with microsoft you never know!
