Are you saying that 32 bit on a 64 bit architecture kind of "wastes" registers because data is only using half of the space available in each register? I haven't written assembler code in some time (and never on 64 bit architecture) but afair a register is either in use or it's not, which means it shouldn't matter how much data it contains. Neither should a 64 bit value use more registers, because on 64 bit architecture all registers are 64 bit wide. The only part of a cpu which could be affected is its cache, which can only store half as many 64 bit values as 32 bit values. Long story short, I'm still confused what you're trying to say
No announcement yet.
Ubuntu 12.04 LTS: 32-bit vs. 64-bit Performance