i've never tried any of them, but i know there are programs out there for this exact purpose that eat cpu cycles so the dos game runs at the right speed
if your cpu is unlocked, you could always seriously underclock your processor too and use a boot disk and boot to pure dos and play it from there too
---- edit -----
i'm still half asleep
, your cpu doesn't need to be unlocked, drop the fsb down to about 10 and have fun retro gaming
