This used to be true, I haven't tried the latest versions of MAME so I'm not sure anymore, but when I'd use Mame32 .121 (64-bit), I'd get like a 10% performance boost in SF Rush, but you have to do the sound work around when using .121, and it's hard to find now I think. I got it sitting around somewhere though.
Another tweak I'd do to the sound is, since the arcade machine had 4 channel sound, It doesn't sound quite right in MAME (with 2 channels), I'd set the sound to 50% in channels 1 and 3 (if I remember correctly), or it could be channels 0 and 2 (I'm going off memory) and it would sound more like the arcade machine when you turned the sound up.