I ran some Quake benchmarks on my newly rebuilt P100 system and my P233MMX system for comparison.

The P100 has 16MB RAM and a 2MB S3 Trio64V+ with the VBE drivers. The P233MMX has 64MB RAM and a 16MB RIVA TNT PCI.

At the standard Quake resolution (320x200, right?) the P100 comes in at 20.7 FPS and the P233MMX at 52.4FPS. As expected.
However at 640x480, the P100 comes in at 23 FPS and the P233MMX at 18.3FPS.

I've run these tests several times, and the results are basically the same each time.

So not only is the P100 faster than the P233MMX, the P100 is faster at higher resolution than it is a lower resolution.

The best reasoning I can come up with is that the S3 card has superior DOS performance to the TNT. Other than that I don't know how to explain it.