Here it is - the best of the best in AMD's portfolio. Athlon64 FX-53 remains unchanged except for the upgraded HyperTransport that now runs at 1 GHz rather than 800 MHz, giving it a fractional performance bonus over Socket 940 solutions. The only reason it performs slightly better than the 3800+ is due to its 1 MB L2 cache.
Unfortunately, AMD decided to do something that is very uncommon in the processor business - the price of the FX-53 was increased from $733 to $799 for 1,000 units. As we are used to regular price cuts, an increase is rather irritating. Sure, we are talking about an excellent product, and there's definitely nothing wrong with selling the top product at premium prices, but isn't that strategy a bit over-confident? Anyway, if you can afford to get a FX-53 system, you likely won't care about $66.