AMD’s 90nm Winchester CPU

Features and Specifications

Athlon 64 3500+ (90nm)
Freq/Cache: 2.2GHz / 512KB-L2
Process Technology: 90nm Silicon on Insulator (SOI)
Approximate Die Size: 84mm squared
Nominal Voltage: 1.40 V
Max Thermal Design Power: 67 W
Max Icc (processor current): 45.8 A

Athlon 64 3500+ (130nm)
Freq/Cache: 2.2GHz / 512KB-L2
Process Technology: 130nm Silicon on Insulator (SOI)
Approximate Die Size: 144mm squared
Nominal Voltage: 1.50 V
Max Thermal Design Power: 89 W
Max Icc (processor current): 57.4 A

The difference between 90nm and 130nm:

Probably the most important aspect of moving to a 90nm process is cost, plain and simple. I’ve seen estimates where moving to a 90nm process allows AMD to generate 72% more processors per wafer. For a company like AMD, who doesn’t have the resources of an Intel, this is huge. The benefit of lower manufacturing costs for AMD also benefits us, the consumers, simply by virtue of lower costs and more processors.

Are there other benefits of moving to a smaller process? Can AMD make the changes that Intel couldn’t, and can AMD make 90nm processors a success?

What is obviously different is the die size. The 130nm die measures 144mm squared, while the 90nm die measures 84mm squared, a reduction of over 40%. The positive here is that by shrinking the die, you also shorten the distance electrons must travel; another benefit is that less voltage is also required to move them. The negative of shrinking the die is thermal leakage. When shrinking the die, the space between the traces shrink, leading to current leakage, current leakage means more heat, and more heat means a hotter running processor.

Another issue to consider is thermal density. The 90nm Winchester has the same number of transistors as the 130nm Newcastle, which increases its thermal density. By comparison, the 90nm P4 3.2 Prescott has 125 million transistors, while the 90nm AMD 3500+ has 68.5 million transistors. Although the die size is the same, the Winchester should run cooler because its fewer transistors mean the thermal density of the AMD 90nm die is less than Intel’s 90nm die, requiring less current to power it. The 130nm Newcastle requires 89W, the 90nm Prescott requires 103W, while the 90nm Winchester requires only 67W!

The main issue to this point with the 90nm technology is high temperatures, but I believe the combination of fewer transistors (less thermal density) combined with a smaller die (less voltage) will actually lead to a much cooler CPU. A much cooler CPU tends to be a better performing CPU. Let’s see how the new 90nm processor fairs against its 130nm counterpart, both thermally and in performance.