I take it you have a Mediator PCI 1200 then. I never succeded in
getting my Voodoo 4 4500 working, but Voodoo Banshee and Voodoo 3 3000
works as it should. As a side note, the Voodoo 4 4500 works fine in my
Mediator PCI 4000.
If you decide to replace the Voodoo 5 5500, go for a Voodoo 3 3000 as
it will enable you to run Warp3D; Voodoo Banshee doesn't.
As I see it, there is no reason to run both. I never tested myself,
but I have been told that Voodoo is faster than BVision. The only game
that has a problem with Mediator/Voodoo is WipeOut 2097; it has some
funny looking graphics during load, but the game looks as it should.
Voodoo is easy to install; as with any other software, just read the
docs.