Athlon 64

What all manufacturers, partners or not, are waiting for is AMD's Athlon 64 and Opteron parts. As we mentioned yesterday, with Intel slowing down their clock speed ramp AMD has a great opportunity to make a splash with Athlon 64 on the desktop.

AMD is fairly certain that they will be able to deliver Athlon 64 to the desktop at the end of Q1 2003 or the beginning of Q2 2003. Realistically, it will be closer to the start of Q2 2003 but we'll keep that tight range open for discussion. We reported earlier this week that current Athlon 64 samples are running at 1.4GHz (software and hardware developers just received 1.8GHz samples) and today AMD reassured us that they will have a performance leading part at launch. With the current 1.4GHz CPUs weighing in at around the speed of a 2.2GHz Pentium 4, we'd expect great things from a 2.0GHz processor on a fully tuned platform at launch; luckily AMD will be up against no faster than a 3.20GHz Pentium 4 at launch.

We asked the question of whether AMD expects to see a 64-bit desktop version of Windows at the Athlon 64's launch and their answer was an expected "it would be nice" but clearly unlikely. It was quite clear that Microsoft was never going to have a 64-bit desktop OS ready for the Athlon 64's launch had it been the end of this year, and even as we move into 2003 it will definitely be after Athlon 64 is out before Microsoft makes the move.

As AMD mentioned, there are a good number of betas and preview versions of the 64-bit OS floating around but nothing close to final yet. By far the biggest issue Microsoft is encountering is driver support; unlike the server market where you don't have to worry about much backwards compatibility with older hardware, with a desktop OS Microsoft must make sure that all sorts of older peripherals will work just fine with the new OS. Unfortunately that means that all device drivers have to be ported to x86-64 as you cannot run 32-bit device drivers in a 64-bit OS. Getting that sort of driver support will take some work, although all of the latest products should have no problems with driver availability (NVIDIA has already released IA-64 GPU drivers and we're certain an x86-64 version wouldn't be too much to ask).

We also had a number of questions about the Athlon 64's architecture and how the on-die memory controller changed the rules of the game. The biggest question on everyone's mind is how difficult is it to support DDR400 and future memory technologies?

It has always been AMD's official stance that the Athlon 64 will support a single channel of DDR333 SDRAM through it's on-die memory controller. Obviously when the Athlon 64 is out, DDR400 will be picking up some momentum (thanks to Intel's endorsement of the technology) and an eventual migration to DDR400 support would be nice. Unfortunately DDR400 support will only be available through a new revision of the chip, although we're hoping that AMD may forego DDR333 support in lieu of DDR400 at launch, assuming that DDR400 is in enough supply. The reason for a new revision of the chip is only to optimize internal timings for DDR400 operation; remember that with the memory controller now on-die it is no longer necessary to make sure the memory runs in sync with the FSB frequency, as there is no "FSB" to speak of. The results of this are that internal datapaths within the chip's memory controller must be optimized at new frequencies in order to guarantee top performance.

What you can take away from this is that it doesn't mean that DDR400 won't work on first-generation Athlon 64s, but it may not run at peak performance. We brought up the idea of our more "adventurous" (read: all) readers running the first Athlon 64's out of spec with DDR400 memory settings and they confirmed that it could be a possibility. It would be up to the motherboard manufacturers to expose the appropriate settings in their BIOSes. An overclocked Athlon 64 with DDR400 support would not, in theory, outperform a new revision with optimized DDR400 support.

Implementing DDR400 support in the Athlon 64 is a relatively trivial matter compared to supporting a new memory technology like DDR-II for example. The major differences between DDR-I and DDR-II exist in the interface, or the in the way the controller talks to the memory; the signaling is vastly different as are the electrical characteristics of the interface. The end result is that the move to integrate DDR-II support is much more difficult but manageable of a task for AMD. Once again, DDR-II support would come in a future revision of the chip; and unlike DDR400 support, you wouldn't be able to overclock your Athlon 64 to support DDR-II.

The fact that AMD will now have an on-die memory controller means that they are less likely to introduce support brand new memory standards on their own but rather wait until industry support is there and then release Athlon 64 support. This could work to the industry's advantage as we won't have another company supporting another set of varying memory standards. The reason AMD will have to be cautious of what they support is simple; just think about what would have happened to Intel's CPUs if they had integrated a Rambus memory controller in them back in the i820/Pentium III days.

Packaging was another question we've been curious about; the 754-pin Athlon 64 will definitely be the most expensive desktop x86 CPU from a packaging standpoint, but how will that translate into CPU and overall system prices?

AMD admitted that the CPU would come with a premium because of the packaging issue, with the biggest problem being power delivery to the core (read our BBUL article for more information on what factors influence packaging technology). Remember that the only way power gets into the die itself is through approximately 30% of those 754 pins that connect to tiny wires on the inside of the package which finally bring power to the chip. On the bright side, AMD did mention that Athlon 64 chip prices would be competitive with Pentium 4s; indicating that the Athlon 64 would compete with the higher end P4s on price. On the system side, AMD expected Athlon 64 systems to be selling for $1600 - $2300 at launch, which is fairly reasonable.

Looking towards the future, by the end of 2004 AMD expects close to 100% of their desktop production will be Athlon 64. The benefit of producing such large numbers of CPUs is that AMD will be able to significantly reduce the price premium of the Athlon 64's packaging, by then, hopefully to 0% over an Athlon XP.

400MHz FSB & Barton Athlon 64 - Motherboards Galore

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