A bit later than i planned but heres a tidbit of my findings of the Gameboy Advance emu for the Dreamcast being worked on by Troy Davis (GPF):

Dangerous Xmas ran much faster than the last beta i tryed but still not playable with sound off, i will now try with sound on, hmm got to say on this game i noticed no real slowdown with sound on.

next game:

Wonkieguy was really slow, so slow its painful, not sure why such a massive difference in speed between this and dangerous Xmas.

Next up a games called 2origins which featured 4 games in it(an entry to GBAx 2004) this again loaded slow and played slow too, it worked fine but no luck as a playable game.