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AMD swaps sockets

After what seems like an eternity, DDR2 finally makes it to the Athlon 64 platform.

Yet another socket change for AMD? The company’s naysayers will run and run with this one, but the truth of the matter is that no one likes a change in socket. It’s annoying for consumers, motherboard manufacturers, system integrators and even the company that makes processor itself. So why the move to AM2 now?

The reason behind all this socket swapping is down to the integrated memory controller that AMD introduced with the original Athlon 64 range. At the time it was seen by some as a controversial move, because it locks the processor to a single memory technology. The payoff, however, is greater performance due to lower latency and additional performance advantages in multi-core processors. This is because it can eliminate unnecessary memory accesses that can be halted on-chip, rather than the far longer process of sending requests to the northbridge for resolution.

This enables us to shed light on the move to socket AM2. The reason is the introduction of DDR2 memory for the Athlon 64 platform. Technically, there’s no need for the shift in socket; the DDR2 lines could be happily accommodated by socket 939. To avoid confusion and people attempting to use the wrong model of Athlon, AMD has chosen to shift to the 940 pins of socket AM2.

Necessary upgrade
If that figure sounds familiar then it should be pointed out that these sockets are keyed differently to the 940 Opterons. The shift also makes sense as you will, of course, have to upgrade to a new board anyway because you need one sporting fresh DDR2 slots.

As for DDR2 support itself, at launch AM2 processors will support dual-channel DDR2-800. However, we’re told by AMD that unlike DDR1 models that were limited to a maximum speed of DDR1-400, the DDR2 controller will automatically support faster memory speeds, which will be DDR2-1066. The first samples of this memory type are just becoming available.

For testing purposes AMD sent over an AM2 motherboard with 1GB of DDR2-800 memory and the latest Athlon 64 FX62. For a while now AMD has had a good spell wearing the performance crown. While Intel is struggling switching between its outgoing P4 NetBurst architecture and new incoming Core Duo platform, AMD has been free to rule the performance desktop space. Yet monarchs usually have a shaky grasp on their thrones and the FX62 looks like it’s the last triumphant gasp for AMD’s 90nm technology that has, so far, done the company proud.