Sorry but at this moment Halo is an unsupported game by Voodoo cards and/or voodoo drivers. It is a title perfecly matches nVIDIA video hardware specs while it doesn't run well on ATI or other devices like these 3dfx.
The reason why I even tried the Voodoo on Halo is because the MX400 was giving me lag.All setting were turned down low even and it just seemed to slow.Well my B-Day is coming up next week and my wife & mum are going in on getting me the 9600XT. Mass improvment over the MX400 which is just recently new due to the fact that my Voodoo 3 2000 after 5 years crapped out.
EDIT: Is it very hard to flsh the BIOS of this Voodoo 5 5500?