While I have no sales numbers (some old shareholder Pages or related official Quarterly annuncements might come in handy for that purpose), judging by the Download numbers...
...I reckon this is a good guess at the total sales ranking :
- Voodoo3
- Voodoo2
- Banshee
- Voodoo1
- Voodoo4/5
- Voodoo Rush
- Velocity 100/200
- Quantum3D Models
I think that's reasonable.
Voodoo3 was the long awaited (and hyped) successor of the Voodoo2, around or slightly beyond the peak of 3dfx Fame, resulting in extremely large sales. At that time, 3dfx was still No.1, extremely well known with excellent reputation, and everyone was expecting the Voodoo3 to rule
The Voodoo2 is very close to it, as it was as well sold (at the abolute peak of 3dfx) in large numbers.
The Banshee apparently got sold quite alot as well, mainly being a good Price those days I reckon.
The Voodoo4/5 already faced hard competition, and were massively delayed, thus only relatively few were sold (and they were kind of expensive, with the Voodoo4 being not much faster than a Voodoo3 3000 at the same time)
And well, the VoodooRush was bashed by almost every Review Magazine when it was released, so most people stayed clear of it.
Velocities were sold too rare, mainly to OEM's, and the Quantum3D Cards were just way too expensive to ever reach large numbers in sales.