3dfx's VSA-100 was also used on the Voodoo5, which actually surfaced before the Voodoo4. The Voodoo5 5500 contained two VSA-100 processors connected via on-card SLI. This had the effect of increasing performance, but also made the Voodoo5 relatively expensive.
Only the Voodoo5 5500 made it to market, and there weren't many of them sold either. 3dfx planned to create more models, including a Voodoo5 6000 with four VSA-100 chips. But it was cost-prohibitive and never saw the light of day. Not long after, the company went bankrupt and was sold to Nvidia.