I have a K6-3 450 with a V770 Ultra. I also have a Voodoo 3-300 for this machine. I'm only posting my personal experience with this setup. With the voodoo 3 I get a much better 3d mark 99 score!! than with the tnt.
This doesn't seem to be the case with Q-III
though. The timedemo is about 10 FPS slower with the v770 but it doesn't seem to matter at all in regular game play though. Both cards look excellent in Q-III(even the voodoo with out 32 bit support) This is probably due to the excellent Q-III engine.
I think if I had to make a choice between these two great cards for this particular computer, I'd be inclined to opt for the Voodoo. Now, On my cu mine 500@ 700 with a Matrox g-400 MAX The 3d mark 99 is almost double in all tests. I wonder if these benchmarking programs are Intel-centric?
I don't know why even though I have the uber powerfull Intel box I always seem to drift over to the other side of the room where my AMD toy is and play games on that? I love playing on the under-dog. But although it is considerably slower in bench marks than the Intel computer, there is no noticable difference in the quality or immersive experience when gaming on the AMD!!