Er, no, he didn't. The two cards are totally different in terms of performance.
Obviously you will need a PCI-e motherboard to be able to use an X700, but check the main website video section for a review of the X700 comparing it with the 9800 among others.
IMO, an X700XT is a better bet. I think it is the same price as the X700Pro, but comes with faster core and memory clocks, but less memory (128MB vs 256MB), but at that level, the extra memory will not make too much difference.