Here are your "final benchmarks."
Nothing has improved. Get this into your heads: AMD Athlon 64 processors do not need the additional bandwidth provided by DDR2. It just doesn't do them any good. Not even with DDR-800 and higher-clocked memory modules (which are significantly
more expensive than regular DDR-667) did the performance matter. Its an excellent
move from a business standpoint, however. DDR2 is what the future is about (for the next few years) and it scales much better than DDR. That, and many other factors, make this a good move by AMD, and the right time to make the move. However, the performance has not increased over Socket 939, and thus, AMD has little defense against future competitors.