Athlon 64 Memory: Rewriting the Rules

Final Words

With the latest memory chips from Samsung, Micron, and Hynix, the real excitement in DDR memory performance has shifted to the Athlon 64 platform. In our first full-scale roundup of memory on the Dual-Channel Socket 939, we found several DDR400 memories that reached a stable overclock of DDR600 and several more that came very close to this memory speed. It is clear that DDR memory manufacturers are paying close attention to the Athlon 64 platform, since we are seeing familiar memory reaching further on Athlon 64 than what we saw on our Intel 478 platform.

A 50% overclock of memory is nothing short of incredible, but that is exactly what we are talking about with most of these memories. In comparing memory at the same CPU speed with different memory bus speeds, we also see that, in general, the improvements in memory performance are real. The latest memories are still fast enough at higher memory speeds to outperform DDR400 2-2-2 performance.

The very top of the memory tests are the most revealing results here. Despite the fact that several memories reached DDR600, highest performance was at the fastest speed the memory could achieve with a 1T Command Rate. This varied from DDR546 to DDR590, and it was at those 1T memory speeds that the best memory performance was consistently achieved.

All six memories tested here performed very well in our Athlon 64 tests. They all outstripped our expectations when we first set up the Athlon 64 test bed. However, a couple of memories do stand out. The OCZ 3200 Platinum Rev. 2 was fastest at both DDR400 and it also achieved the highest 1T speed that we found in our tests. Since these are the same chips used in four other tested memories, we can only suspect that OCZ is doing something unique in their SPD programming. We would suggest that the PCB might also be responsible except for the fact that a couple of other TCCD memories are using what appears to be the same PCB. As we saw in our 2-2-2 roundup, the Crucial Ballistix also stood out for the incredibly fast timings that the Micron-based Ballistix achieved in the DDR433 to DDR533 speed range. The Ballistix was faster through much of the tested range, and the OCZ was best at the top and bottom.

This should not take anything away from the excellent and consistent performance of the G. Skill TCCD and Geil 3200 Ultra X. Both exhibited a very wide range of memory speeds and they were both competitive at every speed. The PQI 3200 Turbo was generally a bit slower, probably the result of tweaking for the Intel platform. We suspect that this would quickly change if PQI updated their SPD programming for better Athlon 64 performance. Still, there is nothing to really complain about in the performance curve of the PQI memory.

It is a bit early in Athlon 64 testing to select an Editor's Choice, but the OCZ 3200 Platinum Rev. 2 and Crucial Ballistix are former Gold Editor's choices. These two memories were also the standouts in a group of standouts in these tests. The Hynix-based OCZ 3700 Gold Rev. 3 takes a different approach to memory performance, but it is still an excellent choice, if it can be bought for a lower price than the Samsung TCCD and Micron-chip memories.

We learned that the Athlon 64 quest for a 1T Command Rate is worth the search, but you also will need the tools to allow the best overclock with memory on the Athlon 64. As surprising as it will seem to some, that should include the highest quality power supply that you can find at 500 watts or more. We found that replacing a well-respected 465 watt PS with a 520 watt PowerStream allowed even higher memory overclocks. This was true with both the power-hungry nVidia 6800 Ultra as well as the more mainstream ATI 9800 PRO. If top memory overclocks on the Athlon 64 is your goal, don't skimp on the power supply. Putting the best PS that you can find in your system will pay off in higher memory overclocks with greater stability.

The memories tested here were a cross-section of the best current memory that you can buy. They used Samsung TCCD, Micron G die, and Hynix DT-D5 memory chips. All of the memories based on these current chips performed incredibly well on the Athlon 64 Socket 939. The Samsung TCCD, in particular, seems to be much better on Athlon 64 with recent chips than what was seen in early testing of TCCD. With Athlon 64 performance this good, we can only wonder how long it will be until AMD makes DDR500 or DDR533 a standard DDR memory speed on the Athlon 64 on-chip memory controller.