AMD Athlon 64 has to be one of the most diverse CPU platforms when it comes to its socket layouts. Originally starting off as a Socket 754 single channel memory design for the desktop and a Socket 940 for servers, this soon changed to include a 939 variant for the desktop with dual channel memory. Socket 754 stayed for the value-end with Sempron and Socket 940 for servers.
AMD Athlon 64 has once again been given another socket, but this time AMD is retiring its previous two desktop sockets - namely Socket 754 and 939 - and replacing it with a single Socket AM2 based on a 940-pin layout arrangement.
In server markets, AMD is also going to retire the Socket 940 Opterons in due time to make way for the LGA based Opterons giving AMD only two sockets to worry about. Intel recently had Socket 478 and 775 but now only 775 exist for desktops in new CPU's and soon to see the end of 604 in servers for LGA771.
AM2 is a new socket and hence it does add one new feature to the mix for AMD Athlon 64 and AMD Sempron based on this new socket - that being DDR-2 memory support. Today we are going to pit an AMD Athlon 64 X2 3800 AM2 against a similarly clocked Socket 939 CPU to see just what, if any, gains come from the new memory interface for AM2 based processors.