Clues in Prescotts Microarchitecture

By Mark Hachman  |  Posted 2004-01-29 Print this article Print

The Prescott chip will be Intels first to be manufactured on the companys new 90-nanometer process, which will allow headroom for faster designs. However, as with its previous processors, Intel may look to a variety of ways to boost processor performance beyond higher clock rates, including hyperthreading, larger caches, multiple cores and the multiprocessor virtualization "Vanderpool" technology shown at the Intel Developer Forum last September. However, for many industry watches the Prescott architecture itself has provided evidence for 64-bit capabilities.
The "Northwood" Pentium 4 contains 55 million transistors; the Prescott contains about 125 million transistors, according to Peter Glaskowsky, editor of the Microprocessor Report and an analyst for In-Stat/MDR of San Jose, Calif. Even factoring in the additional transistors used for expanded cache, new speed paths, and additional logic to process the new instructions, the Prescott contains far more transistors than its predecessor.
Some analysts said that the extra transistors will be consumed by cache redundancy, the need for extra trace cache, and the normal safeguards built into microprocessors to prevent errors. Glaskowsky didnt buy it. "I think of that lot of that ratio is unaccounted for," he said. Financially, though, the addition of the extra logic may hurt Intel. By way of comparison, Glaskowsky noted that IBMs PowerPC 970FX, a 90nm part, was about half the size of the IBM PowerPC 970. "Its considerably cheaper, about a third of the manufacturing cost, although the packaging is essentially the same," he said. "Its faster, consumes less power, and enables new systems like the [Apple Computer Inc.] Xserve G5." The current "Northwood" Pentium 4 measures 132 square millimeters, and Prescott is expected to measure about 112 square millimeters, a 16 percent decrease, Glaskowsky said. "Thats not so very big in terms of manufacturing costs; thats not [a] two-to-one [ratio] in any way," he said. Prices for the new Prescotts are expected to be roughly on par with their Pentium 4 counterparts, according to sources, somewhat mitigating the smaller die size. One dealer said the price for the new 3.4GHz Pentium 4 Extreme Edition would be the "real whopper," however; costing over $1,000 per chip. Next Page: 64-bit Software Infrastructure Needed.


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