The Mac uses a Radeon 9600XT GPU. Many thanks to the assistance from @Jeroen Diederen .

I have two monitors attached to the Radeon card. One is a Samsung 32” hooked up to the DVI port, the other is a 20” Apple Cinema Display attached to the Apple Cinema Display port (VGA).

It will not boot successfully with both monitors attached when powering up the G5. It only boots successfully with the DVI monitor attached.

Once the desktop is loaded, I can attach the Apple Cinema Display, and after setting the resolution to 1680X1050 on the Samsung, the Apple Monitor will show a “mirrored” desktop. I cannot get the displays set to show an extended desktop.

The Monitors preference, and ARandR both see and recognize the two monitors but neither has the ability to extend the desktop.

I am able to boot up in XFCE as well as MintPPC64. When booting in XFCE, the Displays preference actually has a check box to display the desktop as mirrored. Unchecking that box kills the Apple Display (goes black).

I have run Xorg -configure and the xorg.conf shows the existence of both monitors. I’m just not sure how to change the file to do the following:

1) start up properly with both monitors attached
2) show an extended desktop

If anyone has done this successfully, I’d love to know what was done to get this configuration to work.