AGP Dual Compatibility
From OS X:
From OS 9.1.x or 9.2.x (will not work with earlier versions of Mac OS):
In the New Report window, check "System Profile" and "Hardware overview" check boxes.
When the report window appears, click the radio button next to "Text document."
Identify your machine type by checking the "Model name:" line.
"Power Mac G4 PCI Graphics": this model uses the PowerForce G4 ZIF and is not compatible with dual processors.
"Power Mac G4 AGP Graphics" or "Power Mac G4":
Read the last text under the "Hardware overview" section.
If it says uni-n: 7 (or greater) your machine is dual compatible.