OCJB  The AGP card that I installed, though originally deemed as "Quartz Extreme Compatible", showed up in System Profiler as incompatible.

I removed PCI Extreme from the system with help from the author due to the incompatiblity and upgrading the system beyond 10.4.3. The author has posted this information on the PCI Extreme! 3.1 MacUpdate page (http://www.macupdate.com/info.php/id/8979/pci-extreme%21) and probably other places as well.

Here is another reference which may be helpful:

http://everything2.com/?node_id=1733055

All well now on the G4 Sawtooth...  
(Version 3.1)

OCJB  I think I misunderstood the use of this file. I have an AGP PowerMac G4. It also has an ATI 9200 Mac Edition in a PCI slot. I was trying to enable Quartz Extreme by using this hack. My system will not reboot. Get grey screen, then blue screen. Nothing else, so I cannot get in to remove the changes made. Please help...  
(Version 3.1)