My brother has a Duron 1000 and a Voodoo5. I fired it up one day and the only way it would run is in 16 bit color if you want decent framerates (I was getting probably close to 25-30 most of the time). But with 16-bit color for some reason it looked terrible (very washed out colors across the board) and I'm not even that picky.
32 bit color was a joke. I was getting literally about 5 fps, totally unplayable even at low res.
So I would guess that a Voodoo4 would be a waste of time.
You might think that it could be because I was using a Duron instead of an Athlon, but I can assure you the difference would be miniscule if any.