Unfortunately the current speed of the gameboy advance emulators depend on the speed of your processor, so if you have lower than 700mhz, you're gonna have some chop in the game. On this current computer which is a 333mhz with a 16mb voodoo3 video card, the thing runs like crap, but when I was at school on a pentium III 1.4ghz with a Geforce 2 I believe it was, it ran perfectly smooth, and my friends 900mhz pc also runs the emulator very smoothly.
I'm not sure exactly why this is because I can run like Zsnes, Snes9x, Gens, NeoRage 0.8c perfectly on this 333mhz, but gameboy advance emulators run like crap. I've tried a few of them as well, and its just something about the coding.
-Luke