It seems the Mac OS X 10.3.7 updater breaks Quartz Extreme on Macs that have PCI video cards. There is a way to get back Quartz Extreme, and this is how.
You need to install CoreGraphics.framework, but you will need the 10.3.6 combined updater and Pacifist to do so. Drop the updater package onto Pacifist and navigate to /System -> Library -> Frameworks -> ApplicationServices.framework -> Versions -> A -> Frameworks, and select CoreGraphics.framework. Now press Install, select Replace from the appearing dialogs, and restart. Next you can use PCI Extreme to re-enable PCI Extreme.
You can also enable it manually by running TextEdit as root in the Terminal. Type sudo and then press the spacebar, then control-click TextEdit, navigate to Contents -> MacOS, and drop the enclosed file in your terminal window. It will now ask for your password, and TextEdit will open as root. While in TextEdit, open Configuration.plist, found in /System -> Library -> Frameworks -> ApplicationServices.framework -> Versions -> A -> Frameworks -> CoreGraphics.framework -> Versions -> A -> Resources. Now just change IOAGPDevice to IOPCIDevice. Repair permissions and restart. Doing this should get you Quartz Extreme while using Mac OS 10.3.7.
Mac OS X Hints
http://hints.macworld.com/article.php?story=2004121819273427