AMD 2004 CPU Roadmap Update

Sitting in a seemingly endless number of meetings at CES, you quickly realize that keeping up with all of the product releases, socket flavors, chipsets to wait for and GPUs to lust after is virtually a full time job.

We try and ease the burden as much as possible by providing you with coverage as soon as we get the information, but what we're seeing at the start of this new year is that with so much changing it's necessary to work a little harder to simplify things. The Intel world is pretty easy to follow; Prescott is due out soon in a Socket-478 flavor, followed by a LGA-775 version. By the end of this year Intel may begin sampling Tejas, the successor to Prescott but very little is known about the chip. Tejas has been rumored to be a multicore desktop chip, however we're now receiving information contrary to what we had once thought.

On the chipset side, we are all waiting for Grantsdale and Alderwood from Intel, the successors to the 865 and 875 platforms. But where Intel's 2004 roadmap is pretty straight forward, AMD's is a bit more cluttered with the confusion of varying cache sizes, Socket-939 and model numbers. Although most of the information about AMD's future plans have already been leaked on the net, we decided to put together a quick reference page to AMD's 2004 CPU roadmap to go along with our recent coverage of chipset plans.

The roadmaps are divided according to CPU socket and the rest is self explanatory - we hope the information is concise and useful:

As of now, the fastest Socket-754 CPU will be the Athlon 64 3700+; current motherboard owners looking for an upgrade path can look no further than the 3700+ running at 2.4GHz.

What's interesting is that the model numbers seem to scale more than linearly with clock speed, something we noticed with the Athlon XP that eventually led to its misleading model numbers. In the case of the 3400+, a 10% increase in clock speed over the 3200+ resulted in a 6.25% increase in the model number (resulting in the 3400+). However, if we look at the 3700+, a 9.1% gain in clock speed results in an 8.8% increase in model number. Where we cannot draw a parallel to the Athlon XP model number situation is in the fact that the Athlon 64's on-die memory controller does allow the CPU to scale much better with clock speed. It could very well be that AMD is counting on the Athlon 64's performance scaling much better with clock speed than Prescott, thus justifying the increased model numbers.

What's also worth mentioning is that the 3700+ will be the last 1MB L2 cache Athlon 64 to hit the market, every other Athlon 64 will feature a 512KB L2 cache. The smaller cache size brings us to the difference between the two Athlon 64 3400+ processors listed in the chart above; the current 2.2GHz 3400+, as you know, features a 1MB L2 cache. In the next quarter, AMD will bump the clock speed of the 3400+ to 2.4GHz and cut the cache in half in order to maintain the performance rating.

The last thing to note are the two Socket-754 Athlon XPs on the chart; although clock speeds have yet to be determined, you can expect these two processors to feature an on-die memory controller just like their Athlon 64 brothers but have their 64-bit support disabled. The reduction in cache size to 256KB will decrease 32-bit performance by a noticeable amount, but they will make a good successor to the current Socket-A Athlon XPs.

The new Socket-939 platform will bring dual channel support to the entire line of 64-bit AMD processors, and it will also take away half the cache from all but the FX processors. Although the Socket-754 3700+ features a full 1MB L2 cache, the Socket-939 version will not be given more than 512KB. What's interesting is that the two processors carry the same 3700+ model number, running at the same 2.4GHz, while the Socket-754 version features twice the cache. AMD seems to be indicating that the advantage of a 128-bit memory interface will offset any performance loss incurred by halving the cache. We have not seen much data to support this theory, but we'll keep a close watch on it.

If you'll notice, there are two 3700+ processors on the roadmap above and since we're trying to clear up confusion, here's an explanation: the Q4 Socket-939 processors are supposed to be based on AMD's 90nm process (that includes the 4000+ and the FX-55). AMD has demoed 90nm Opterons already, but they were running at 800MHz so there's no indication of how well AMD will be able to stick to this roadmap. If we were to expect any deviation from the roadmap as it stands it would be in Q4; new manufacturing processes are not easy to ramp up as we've seen time and time again from both AMD and Intel (Prescott anyone?).

Finally we have the quickly demising (at least on the desktop) Socket-940 platform, the FX-53 looks like the end of the line.

We hope this has been helpful; if you'd like to see similar quick reference articles about other companies let us know.