I would say pretty much they'll be the same, but as always it depends on what get the compiler ends up generating. Likely it'll be something like: mov ax,0x###

I would say pretty much they'll be the same, but as always it depends on what get the compiler ends up generating. Likely it'll be something like: mov ax,0x#### mov bx,0000 cmp ax, bx je equal I say same cause the order of the data moves into the registers shouldn't matter in terms of perf. I 'guess' If you happen to see a minimal difference it would be because an interrupt happened in the middle of the execution,or there's some funky compiler optimization for one of the cases or if... ALL GLORY TO THE HYPNOTOAD.