Addendum:

>> I still have a Radeon 9200 128MB (Mac) PCI GFX card that I used [...] in my
>> PowerMac G5 [...] PCI slot, now whether that will also work in combination
>> with a Radeon 9600 AGP card [...] I don't know, but it might

> MorphOS cannot use more than one Radeon card at a time. That's a driver restriction.

...or can it?

"If legacy W3D support is important [...], you can also stick R9xxx card in G5 machines to have both raw speed and classic compatibility. One of my friends did this kind of solution."
https://amigaworld.net/modules/newbb/viewtopic.php?topic_id=43689&forum=45#832416


Edit: On the other hand, "raw speed" may very well not refer to a primary R300+ AGP graphics card but to the G5 CPU, which would mean the R200 graphics card is actually the only graphics card in the system.

[ Edited by Andreas_Wolf 10.04.2020 - 20:33 ]