Again you can see the order of importance, now for Sin (Glide): First bus speed, second the chip clock. Of course there is not much of a practical difference at only 640x480.
The higher clocked cards are faster. Sin is based on an enhanced 3D engine of Quake II, which has some additional features and thus consumes much more performance.
All five SLI solutions are fast. At higher resolutions the amount of data becomes larger, there's where we should go looking for differences.
The Diamond cards prove to be better optimized for large data amounts. It has pushed the faster clocked Quantum3D card from first place.
The same result as with Quake II: The 8 MB Diamond cards are indeed faster than others at the high resolution of 1024x768.