I've now tried 4 different Radeon 9xxx graphics cards in my AmigaOne XE, all of which *should* have worked, but none of which actually do. 3 were AGP...
I spoke to the TOGA tech today, telling him about your problem. He advises that you reflash the BIOS of the Radeon cards. They are probably set for PC, and you should reflash them to Mac (which is the BIOS for any non-PC computer like the A1). Then the cards should work.
That's what he has discovered in his experience,
Robert Bernardo
Fresno Commodore User Group
http://videocam.net.au/fcugThe Other Group of Amigoids
http://www.calweb.com/~rabel1/Southern California Commodore & Amiga Network
http://www.sccaners.org