I did try Mame OS X vers.114, on a Mac Pro Quad core (at the Apple store a couple of months ago) and KI1/2 was dog slow, and un playable. Then I tried one of their iMacs and a Macbook Pro, same performance. Still unplayable. Now, I never got a chance to test the Apple stores macs with SDLMAME (requires admin rights to copy over SDL.framework), or Macmame .103u2. I can't believe its this hard to get a real answer and proof if KI1/2 can run on a Mac OS X, or using Boot Camp in Windows XP on a Macbook Pro (Santa rosa models). Don't know if I'm going to have to research a way for a thumbdrive to boot camp off the thumb drive just to test this out. And no, I don't just want a dedicated Windows PC machine to play my Killer Instinct 1 and 2. I know I want to up grade my mac mini (2nd gen 1.4ghz PPC, 1GB SDRAM) to something new.