"Important: Whenever you replace a processor with a new processor, you must run Apple Service Diagnostic (once the computer is reassembled). You must also run the diagnostic if you re-install the same processor but in a different connector from the one in which it was originally installed. Apple Service Diagnostic for Power Mac G5 is available as a download from the Disc Images section of the Apple Service Source website. For more information, see Thermal Calibration in the Troubleshooting chapter."
this is from a repair manual somewhere. I think it helps explain what the cd is that im looking for.