That's sad... Personally I have a Radeon 9000 pro in my G4 AGP and a 7500 in my Cube. Perhaps your card is a different version which isn't compatible with Mac ROMs?
I have a Radeon 9000 Pro too and I really like that card, but performance in Leopard seems more consistent when I have a Core Image card in here like the Geforce 6200, which is what I am using right now. The problem with the 6200 is that there is no 2D/3D acceleration in OS 9, which means no DVD playback and no 2D/3D accelerated games. My hope was to have the 6200 in the AGP slot and the Radeon 7000 in the PCI slot and use my DVI switch box to switch between them. Say I wanted to go from Leopard to OS 9: I would select OS 9 from the Startup Disk control panel, restart, hit the button on the DVI switch for the input the R7000 is connected to, and voila! I would be booted into OS 9 with 2D/3D acceleration enabled because the R7000 would be the active GPU. Who knows if this would have worked, but I thought it was worth a try. I think I will either try to find a pre-flashed PCI GPU, a genuine Mac edition, or just spend the cash on a PM G5 and move all my PPC Leopard stuff over to it and have my 1.5 ghz Sawtooth be all about OS 9.
I tried to see if I could find a compatibility list of PC cards that can be flashed or brands to avoid, but I have yet to find such a document. Oh well, at least my VisionTek card was only $15 and if I can find working drivers for Windows 98 SE, at least my Compaq will finally get a GPU upgrade. Not sure if the R7000 is the most powerful GPU I could have put in there, but it would still be a step up from its integrated graphics.
I successfully Flashed a radeon 7000 64mb PCI card that is in my B&W. I used graphicelerator v1.3.4 & ATIhack_Radeon7000AGP-PCI_reduced.rom.zip from macelite IIRC. Worked like a charm, first time.
Yep, that's one of the ROMs I tried. Thanks anyway though. I forget which version of graphicelerator I used, but it was whatever the latest version is on Macintosh Garden. I ran it under Tiger (I have it installed on the same partition as OS 9) both with and without safe boot.