I've just ordered one of these as it was the card I has back in the day. I was scouring the net for info (including here). I found a copy of the manual at falconfly.3dfx.pl, it's in Russian so a bit of pasting into a translator is required, just scanning the diagrams etc. not sure if the jumpers mentioned or not. There are a bunch of other manuals from creative etc. on the site too, along with a mass of technical, coding and other nice stuff re 3dfx though the manuals are in a range of languages (some English). Bit more searching here and the answer is - Voodoo Banshee JP1 Jumper Block - What does it do?