Athlon 64 for Socket 939: What’s New?
AMD times a few minor innovations in the architecture to the launch date of Socket 939 CPUs, but before proceeding to them, I’d like to say a few words about the newly-baked CPU socket first. These are Athlon 64 processors in the new form-factor:
There’re no differences on the lid, save for the marking
Socket 939 CPUs have a different pin configuration than Socket 940 and Socket 754 ones
It is clear that the different pin configuration of Socket 939 makes these processors incompatible with the older Socket 940. Moreover, there are significant differences in the functions of the same legs of Socket 939 and Socket 940 processors. Thus, Socket 939 and Socket 940 and, moreover, Socket 754, are not compatible with each other. The new Socket 939 processors require new mainboards with the appropriate CPU socket. The cooler retention mechanism has remained the same, though, and you can use a cooler for a Socket 940/754 processor in a Socket 939 system.
So, the Athlon 64 processor has grown extra legs, standing now on 939 pins instead of 754. This is because of the dual-channel 128-bit memory controller that came to replace the older single-channel 64-bit one. Unlike in Athlon 64 FX and Opteron processors, used in Socket 940 systems, the memory controller of the Socket 939 Athlon 64 supports ordinary (non-registered) memory modules. This makes the entire platform cheaper (non-registered modules cost less) and faster (registered modules have bigger latencies).