On the X5 300 running WM2003, I got probably 85% speed without sound, and 75-80% speed with. I can't give you an exact frame rate, as the emulator I was using, PocketSNES Bleeding Edge, slows down considerably when FPS is displayed (perhaps it's a benchmark mode?).
If you already have an X3 300, try this emulator:
http://paqpark.nuclearfallout.net/pr...pocketsnes.php
I'm using the 1/16/03 release, though I've heard the 10/8/02 release may be faster.