I am having very similar problems but my cards are recognized and they show up as attached. I can get the realtek card working correctly but I cannot get the voodoo3 working at all.
The modes show up in screenmode even, but when I choose one either the machine doesn't show anything on the second monitor I am using for testing the modes or the machine hangs. I am already bidding on another voodoo3 but I am very disappointed and I've run out of ideas.
Gabriel