No hard numbers, it's just that I barely got a Sinclair Spectrum emulator to run on a 10MHZ 286. A Spectrum is about 3 MHZ. I got an Atari ST (8MHZ 68000) emul

No hard numbers, it's just that I barely got a Sinclair Spectrum emulator to run on a 10MHZ 286. A Spectrum is about 3 MHZ. I got an Atari ST (8MHZ 68000) emulator to just about run on an old 60MHZ (or so) 486. But it's possible I was getting something wrong: The overhead to deal with, say, an Amiga emulation, might be a fixed overhead, meaning it's 20 MHZ to convert instructions, so a 100MHZ machine would run an Amiga at 80MHZ.