Block fut coins write can quadruple 2D and 3D performance for polygon fills and Z-buffer clears This technology along with its unified structure has one limitation It won't allow you to use the Scanline Interleaving SLI feature that has made the Voodoo so popular.
You can still run a Voodoo alongside a Voodoo Banshee board for high-end 3D gaming though 3Dfx is calling the Banshee its mass-market chip and its Voodoo2 will remain its game enthusiast chip.