most n64 emulators suck for xbox but they are still very early so its expected. as for ultrahle i knoe full well if its emulation limits i have worked on its source myself. i think you took my post wrong. good work on porting it you get cradet there but im simply stating thers alot better open source emus out there. and would make better ports.
when pj64 gets there driver issues solved it will probly preform better then ultrahle comptbaly wise. ultrahle is very fast thow so he has the speed advantege over any other emu. i mean if hes relly good he can probly incrase the ultrahle compatbily and beat the rest.