Video card upgrades available?

I am upgrading my G4 Power Mac MDD dual 1.42 MHz PowerPC (FW 800) that was the first model to have the 800 Fire Wire installed. Apparently, this model is a bit picky about some of the components compatibility. If things aren't just right the computer won't work.

This came with an ATI Radeon 9000 Pro with 64MB of DDR SDRAM video card which has gone belly-up. I not only have to replace it, but I want to upgrade to a faster, better performance card. I have sought the advice of several sources, but most people I have talked to are unfamiliar with this model and their suggestions have all been wrong.

I now have several video cards which I can't use sitting around taking up space. All of them reportedly work on the QuickSilver models, but not on the (FW 800) Model. CAN anyone help me, please???