AMD Athlon 64 3800+ and FX-53: The First 939 CPUs

Final Words

So the verdict on 939 is that it isn't a revolutionary performer, and it won't bring peace to world. But socket 939 is really the finishing touch and final polish that the Athlon 64 line has been waiting for.

We have been waiting for this socket for a long time now, and if we lived in a perfect world, we would have seen a socket 939 like solution (with dual channel and all desktop Athlon 64 processors on one platform) from the beginning. Of course, now that its here, we have reason to rejoice. Socket 754 will become home to the new value line of processors as the current generation of Athlon XP processors fades into the sunset, and 940 pin platforms will still be used for Opteron servers and workstations.

We keep hearing rumors of an Opteron for 939, but we aren't exactly sure why something like that makes sense. Registered and ECC memory support are very important for server and workstation class systems. Stability is the most important factor in such platforms, and taking away such a big part of the equation really doesn't seem logical.

In the final analysis, current socket 754 and socket 940 users won't see gain any real value from "upgrading" to socket 939. The new addition of a dual channel memory controller for unbuffered DDR has no doubt given the Athlon 64 line a small performance increase, but it may not be as much as people had been expecting. The main advantages to socket 939 will be the convergence of the Athlon 64 desktop platform, the ability to use unbuffered RAM in conjunction with high end desktop processors, and the warm feeling that comes from knowing there's quite a lot of memory bandwidth under the hood with a dual channel memory controller on die.

The real reason we aren't seeing more intense performance increases from socket 939 is the same reason we don't huge performance differences between Athlon 64 processors with different sized caches (at least we don't see the variance we see among Pentium 4 based processors): the Athlon 64 is not an incredibly deeply pipelined architecture, and cache misses that result in pipeline stalls don't cause the processor to waste much of its time refilling the pipeline (as is the case with Intel's Netburst architecture in low cache situations). Really, the added bandwidth of dual channel is able to more than make up for the loss of 512kB in cache.

The socket 939 FX-53 absolutely takes the cake in terms of performance (though price will still be a barrier to entry, and an Athlon 64 processor will be a much better value). We are happy with the new line of Athlon 64 processors.

In the final analysis, we aren't talking about the be all end all of platforms and performance, but, certainly, anyone who wants an Athlon 64 system should look no further than socket 939 for its flexibility, overclockability, and performance.