Athlon 64 Memory: Rewriting the Rules

One of the more vexing discoveries as memory performance testing was extended to the Athlon 64 platform was that memory often did not perform the same on both platforms. You simply could not assume that a memory that did DDR550 on the Intel 478 chipset would perform the same on the Athlon 64. We have also discovered that certain memory actually performs much poorer on Athlon 64 than on Intel 478, while other memory consistently performs much better on Athlon 64. With these variations, it was time to establish an Athlon 64 memory test platform and run new baseline tests on some of the best recent memories.

You can see the details of our new Athlon 64 testbed in the recent review, OCZ 3700 Gold Rev. 3: DDR500 Value for Athlon 64 & Intel 478. The decision was made to look to the future on Athlon 64 memory benchmarks with a Socket 939 Dual-Channel test bed. With the recent introductions of the 90nm Socket 939 3000+, 3200+, and 3500+ processors, the starting price for a 939 CPU is now well below $200. This will likely encourage further growth of the 939 as the top-performance platform for Athlon 64. We will soon be bringing you performance and overclocking tests of the new 90nm AMD chips, and our decision to concentrate on Socket 939 for our Athlon 64 memory test bed was influenced by AMD's targeting of the 939 for new product developments.

VIA just launched their first reference boards using PCI Express on the Athlon 64. Later this month, we also expect new Athlon 64 chipsets from others that will add PCI Express capabilities to the Socket 939 platform. While these new chipsets could migrate later to Socket 754 single-channel, the new chipsets will launch with Socket 939. This will further push the 754 to the value side of the Athlon 64 line.

As you saw in our DFI LANParty UT nF3-250Gb: Overclocker's Dream review, the 754 is capable of incredible performance. It is even capable of outperforming the newer 939, since base performance is only about 5% higher for the 939. However, this usually requires the use of one DIMM. Overclocking performance with 2 DIMMs on 754 is normally poorer than 2 DIMMs on 939. While there are many reasons to buy 754 for value and performance, future development will revolve around the 939 socket and dual-channel memory.

To understand better how memory behaves on the Athlon 64, we tested a cross-section of some of the best memory currently available in the lab. This included new Samsung TCCD memory form PQI and G. Skill, familiar Samsung TCCD from Geil and OCZ, top performing Micron-based Crucial Ballistix, and the latest Hynix DT-D5 memory from OCZ. We had originally planned to include the unique OCZ 3700EB also, which had performed well in other Athlon 64 tests. However, OCZ told us EB memory was no longer in production, and we could not find EB in stock at any vendor. We, therefore, eliminated EB from our final testing, since it is no longer available for purchase.