Extending the life of the old dog
One great aspect of writing for an online publication is that you can liberally sprinkle hyperlinks that direct the reader towards previously-written material on the subject. So please take a look at our Phenom II review and the original Phenom (mark I) evaluation in November 2007 if you need a refesher in the technology.Extending the life of the old dog
DDR2/DDR3, the need for a new socket, and, perhaps, some confusionPut simply, Phenom II AM3 chips, which we'll detail on the following pages, are imbued with the same technology as Phenom II AM2+s, but are differentiated in the sense that they're equipped with an hybrid memory-controller that can interface with either DDR2 or DDR3 RAM, although not concurrently.
DDR3 support isn't as thorough as it is for Intel chips, because the AM3 boards, once they become readily available, can only support one DDR3-1,333 DIMM per channel. What that really means is that you can only use a total of two DIMMs, in dual-channel mode, when running speedy DDR3. Folks wanting 8GB of DDR3-1,333 need to look elsewhere.
The new memory-controller, residing on the CPU die, supports up-to DDR2-1,066 and DDR3-1,333 memories. The practicalities of having a double-standard controller means that the new chips are based on an also-new form-factor, AM3, and whilst looking outwardly identical to any other Phenom II, are packaged up in a 938-pin mPGA.
AM3 chips, then, are backwardly-compatible with current AM2(+) boards - 790GX, for example - via a BIOS update, and we've seen numerous board partners trot out AM3 CPU-supporting boards which are just present models with said BIOS update.
Full-fat AM3 boards, which naturally support DDR3 memory, will be based on existing chipsets and trickle to market in the next few weeks. MSI, for one, has already announced pure AM3 boards. We, however, reckon that AM3 products will be best-suited to AM2+ boards for the next three to six months, because DDR3 is still so comparatively expensive: AMD chips, priced at sub-£150 for these new models, would fit into a DDR2 ecosystem.
Just to add a little wrinkle, present AM2(+) chips, and that's every Phenom CPU currently available, won't work on proper AM3 boards: the very nature of the packaging transition prohibits it. Phew!
