AMD's chief scientist on smoke and mirrors

AMD's chief scientist on smoke and mirrors

Summary: As AMD rolls out its 100-million transistor Athlon 64, chief scientist Bill Siegle talks to ZDNet UK about how mirror optics will help future processor plans

TOPICS: Hardware
Q:A decade ago you launched the K5 processor -- AMD's answer to the Pentium -- but ran aground on production problems that scuppered the chip's chances as a real competitor. Are you confident that we will not see a repeat of this with your 64-bit processors?
A: Obviously we have a finite amount of capacity. If we are totally wrong on our projections it could mean a shortfall – but that would be a happy problem for us because our projections don't fill the capacity in that fab (20, in Dresden, where the 64-bit chips are produced).

Frankly we will build capacity as the amount of software and applications grows. The Dresden operation has been three years in production and is working well. This is partly down the dedicated and efficient attitude of the workforce, but also down to our manufacturing, which has achieved high yield levels.

Can you say what those yield levels are?
We don't give out figures, but today we have mature yield levels on the 100-million transistor chip.

What is the next step in the manufacturing process?
We expect to be producing chips on the 90-nanometre production process in volume by the second half of 2004. We have been making prototypes for some time already. We will begin sampling at significant levels in the second quarter. Then 65nm will come in late 2005, with volume shipments expected in 2006.

As you shrink the die process, what will you use the extra space on the die for?
There are three important features that are new in the Athlon 64. First, the Level 2 cache which is up to 1MB –- we have not done that much cache before. Then there is the memory controller, and the HyperTransport links are significant for performance too.

As the die size shrinks, there are several possibilities. Large caches are one thing we are always looking at. Dual cores also become a possibility. At some point in the evolutionary cycle there comes a limit to how far you can improve performance with a single core on a chip. We will see dual core chips on the 90mn process.

Does that mean you will release a dual core processor by late 2005?

Will that mean much larger die sizes, compared to the 197mm squared of the Athlon 64?
No. In a dual core processor, the two cores will share the cache, so we're not talking about a 200-million transistor chip. Consequently, the die size will not double.

What are your predictions for power dissipation?
The Athlon 64 dissipates about 89 watts. Of course we'd like to see this figure go down. As we look ahead, power dissipation is a more pressing in the mobile space than on the desktop. The move to 90nm will help enable lower power dissipation and when that happens we will also make other design enhancements that will help reduce power dissipation in other ways.

Topic: Hardware

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