Thanks Andreas.

I thought built in NIC was referring to the mobo Ethernet ports.

I tried hd4850 in primary slot, no output.

Re a Mac x1950xt. I guess flashing one will be needed. If so, is it better to flash with a G5 bios or a PC bios?
I know the G5 bios flashed card is reported to work with OSX 10.5.8 but what about with MOS?