My ViRGE DX @ 80MHz ran Terminal Velocity okay (no numbers but at a guess 20~30fps, dipping to low teens at points I'd imagine). Screamer was still pretty slow even at 80MHz - definitely < 20fps. Destruction Derby ran OK from what I remember; maybe topping 20fps? GLQuake with S3's wrapper was pretty crappy, and you needed to disable the light map for any meaningful performance. Again, still not great however, and you'd have to play with potato settings for it to actually be smooth.

Even so, these aren't bad cards if paired with a Voodoo. They provide acceleration for a handful of games that don't have any other accelerated ports, so if you like those games, they're perhaps worth it for that, but even then they're not amazing. But they're solid 2D cards.

I gotta try Terminal Velocity, I just remember being completely unimpressed with how Descent2 ran on a Cyrix P200 + S3 Virge.