I got a little time last weekend to swap video cards around and try a few benchmarks, using the Phils dos benchmark suite.

The system:
Gateway PIII 500mhz
128mb ram
win98se
All tests done in msdos mode, not inside win98se proper.

Cards:
TNT2 M64 8mb
Vanta LT 8mb
Voodoo3 1000 8mb

for reference, heres the list of tests: (fps)
1) 3d bench 1.0
2) 3d bench 1.0c
3) chris's 3d benchmark
4) chris's 3d benchmark 640 x 480
5) pc player
6) pc player 640 x 480
a) doom min details (results in realticks for doom )
b) doom max details
c) quake
d) quake 360x480
e) quake 640x 480

tnt2m64 / vanta lt / 3dfx voodoo 3 1000
1) 33.3 / 33.3 / 33.3
2) 316.8 / 316.8/316.8
3) 307.5/306.5/301.4
4) 147.4/147.0/146.4
5) 139.2/139.3/139.3
6) 34.5/34.5/34.6
a) 171.6/174.0/166
b) 652.6/665/626
c) 111.0/111.0/111.5
d) 47.1/46.7/47.6
e) 45.5/45.6/45.7

My guesses:
1) the similar readings are due to cpu bottlenecking?
2) higher resolution benchmarks may separate the cards a little more. is there a better timedemo that is freely/easily available?
3) the voodoo is supposed to be better in theory, but it sure isn't pulling away from the group at all.

I have a rage pro turbo to teat yet, but its PCI not AGP like these 3 were. im interested if it makes a difference.