And a GeForce 6800 will beat that.. if you want, we can see how far this rabbit whole will go. The significance of a GeForce 2 GTS is, its fast, only marginally outside the presumed time period, readily available, and pretty cheap. The GeForce 3 or 4 were released years after the 256 and GF2. The thread devolved into suggestions for alternatives years outside the time frame of the card Xray1281 inquired about. Perhaps that matters. Perhaps that doesn't. There are tons of suitable stand-in's for a 256. Unless you want the card to be period correct. Then there isn't.
In my search for a 256 I looked at what else was available during that time. The Matrox G400, and the ATI Rage Fury Pro. Those became targets for my search. I stopped following 3Dfx after the ATI Rage was released and I never took S3 seriously. So I personally don't know what those manufacturers were doing at the time. Perhaps information an all the video cards which were available at the time the 256 was would add more value then pointing out cards that came years later...
Here is another example. For my 1999 build, I want an Atlas 10k. Not an Atlas 10k II or III which are faster, cheaper, and more available then a 10k I. I want a 10k I. It is period correct for 1999. If someone started suggesting CF cards, or SSD's or whatever else, it would be pretty annoying and dismissive of my wants and needs.
Now if Xray1281 asked, what is a good card for a vintage PC build circa 1999, then let the suggestions fly. But when Xray1281 is like, help me find a 256, and everyone is like, no that's a dumb card. pick something else.. I'm just like... 😕 😕 😐 😐 😕 😕