An 8MB V2 has 2MB of texture memory on each TMU. That is not as general as the current 6MV V1 cards that have 4MB of texture memory on a single TMU. To use the multitexture capability, textures are restricted to being on one or the other TMU (simplifying a bit here). There is some benefit over only having 2MB of memory, but it isn't double. You will see more texture swapping in Quake on an 8MB Voodoo 2 than you would on a 6MB Voodoo 1. However, the texture swapping is several times faster, so it isn't necessarily all that bad.

If you use the 8-bit palletized textures, there will probably not be any noticeable speed improvement with a 12MB Voodoo 2 vs. an 8MB one. The situation that would most stress it would be an active deathmatch that had players using every skin. You might see a difference there. A game that uses multitexture and 16-bit textures for everything will stress a 4/2/2 Voodoo layout. Several of the Quake engine licensees are using full 16-bit textures, and should perform better on a 4/4/4 card.

The differences probably won't show as significant on timedemo numbers, but they will be felt as little one-frame hitches here and there.

(Source: Gamecenter)