AMD has told Fudzilla that its naming structure is rather easy. The higher number means better CPU and 9x00 is better than 7x00.
The confusion is gone, but you will have to know a lot of numbers in order to tell the difference from dual core Phenom and Quad core CPU. You still have a few months before dual cores are available, and by then AMD might easily change its mind.
The X4 is gone from the name as AMD believed that this was too confusing for its customers, as this is what System Integrators and retail / e-tail chains communicated to AMD. Phenom 9600 is the fastest of AMD’s, and 9700 will be faster followed by 9800, and so on.
The big question is what will happen after Phenom 9900 when AMD runs out of numbers. If we are correct Phenom 9900 might be the 2.6GHz part, and after then AMD will have to find an alternative. It will be fun, but AMD is still quite far away from 2.6GHz.
Also, 9xxx means it is a quad core CPU.