I looked around the ATI web site. The 9600 pro and 9800 pro are definitely based on the same chip set and have very similar specs. The differences are:

9600 pro 9800 pro ======== ======== memory 64MB 128MB (the 64MB seems unique to Apple) memory interface 128-bit 256-bit rendering pipelines 4 8 pixel fill rate 1.6Gp/s 3.04Gp/s engine clock 400Mhz 380Mhz (yes, i know this seems reversed) memory clock 600Mhz 680Mhz

--tom