It shouldn't be that slow, I had a DEC Alpha 333Mhz back in the day that could emulate x86 applications to be faster then a 120Mhz Pentium, at least when I tested it with Lightwave under windows NT using FX32. You can achieve higher performance if all you are doing is translating machine code, if you have to actual emulate other hardware (graphics, sound, etc) I can see it going slower then that.

But then again there are not that many games with low requirements, I only found these 2 that looked like they may meet the minimum requirements :P

http://www.lokigames.com/products/smac/
http://www.lokigames.com/products/sc3k/