It is an honest question, though I do believe that it has been asked once or twice. I used to have a 3dfx voodoo 3 card, and it worked on all games after they sold to Nvidia. I do believe that they are (100%) openGL compliant. If you read the system info on the Jedi Outcast page,
it will tell you what is required for the cards. And it says that they have to be 100% opengl supported. Which I do believe that 3dfx put that into all of their cards. All can do is try to play it and if it doesn't work, then you know you might want to get a new card. The voodoo5 is a pretty powerful card, it was made to go against the geforce 3 i believe...though I could be wrong.
I am almost positive that it will work.
If you look, Geforce 4 isn't even supported. But it will work. Alot of games say that they are supported but have alot of unsupported cards on a list that work just fine.
there you go buddy.