Badass, I got it running at 1024x768 with 30 FPS and good audio.
System specs:
Intel P4 3.00GHZ HT
NVidia FX 5900
1GB Corsair Memory
Note: Halo was not even loading at first (it was crashing when trying to read the maps), so I deleted everything Xeon created in the UtilityData folder, then I went to my xbox, loaded Halo, then rebooted back into EvoX, then I transferred everything from my Xbox's X: partition into the UtilityData folder. This way, you can play any map that has been cached by a real Xbox.
Hope this helps, screens (taken at 640x480 for the web):





