Bit-tech.com has Athlon 64 3200+ & 3400+ reviewed. "Fundamentally there is only one real difference between the Athlon 64 and the 940 pin FX51 CPU ; the dual channel memory controller. You would be forgiven for thinking that this will seriously hamper the performance of the 64 but as you will find out later, this turns out not to be the case! Socket 940 has a major disadvantage in that you need to change you RAM to ECC Registered RAM just to get the system to boot up, Socket 754 on the other hand uses your normal, everyday DDR400 RAM." "So despite the high price of the FX51 you also need to buy new RAM and a 940 board to support it, a very costly upgrade indeed. Socket 754 boards are on the whole slightly cheaper than the 940 ones as well as the 3400+ being half the price of the FX51." For full review warp2.. bit-tech.com source:- anandtech.com