I saw Nvidia denied the memo about supporting the 3dfx's driver somewhere.
I believe you guys got new driver from x3dfx, but check their homepage now, and you will see how long they can run.
IMHO, nvidia cards are far slower than 3dfx. The reason nvidia bought 3dfx is NOT they wanted good technolegy. Instead, nvidia simply wants to make sure 3dfx is dead. They won't use 3dfx's chip. And I see no reason they will support 3dfx's cards.