> with Win98
> cli
heh, Win9x is useful in some respects

Try getting rid of the movs to eax, edx, and ebx. You are effectively cutting short your ''dependency chains'' by overwriting the register''s values. To understand these effects, you need to get out of the mindset that the CPU just executes instructions as they come, with fixed latency per op. Usage of the word pairing indicates you''ve been reading Pentium optimization dox - those are long out of date

Once the processor ''sees'' the mov, it is allowed to discard all previous writes to this reg, as long as no other instructions depend on them. I have not dealt with PIIs in depth, so I don''t know how large the window is, nor how clever its data flow analysis is.

BTW, registers aren''t ''fixed'' - there are many more hidden registers that are transparently renamed. Example: add ebx, 1 translates to: 1) take value of architectural reg ebx (more on that later) 2) add 1 3) put it in another temp register ''x'' next clock 4) update mapping of arch regs - the current value of ''ebx'' is in ''x''.

Have a look at the code with your favorite profiler (not just some cheap timer thingy - something that does pipeline simulation), that should clear things up