If you are referring to Mame.....  Use Misfit Mame.   Regular Mame has both standard and fast for both Pac and Ms. Pac.  Misfit will allow you the "turbo button" version that I much more preferred back in the day.  It plays standard, but when you hit the button, Pac/Ms. Pac goes fast, and the ghost stay the same, release the button and all is normal again.