Isaiah processor likely outperforms Silverthorne, Via says

Via Technologies' upcoming Isaiah processor likely outperforms Intel's Silverthorne chip designed for mobile computers based on limited information about the chip that's been made available so far, according to the Isaiah's chief designer.

"Silverthorne is liable to be a little faster than our current C7 [processor], but the new Isaiah will be substantially faster than that," said Glenn Henry, president of Centaur Technology, the Via subsidiary that does processor design for the company.

But don't look for Isaiah processors to match the performance of Intel's high-end processors, the Core 2 Duo and Core 2 Quad.

"The Core 2 is going to be faster. Not massively so, but the Core 2 for performance is the fastest architecture in the world. It will be massively hotter too, and of course massively more expensive," Henry said.

Announced Thursday, Isaiah is a 64-bit processor architecture that is significantly more powerful than the Esther cores used in Via's current line of C7 processors, while consuming the same amount of power. Single-core chips based on the Isaiah architecture will be available soon, with volume production using a 65-nanometer process expected by the end of June.

Intel's Silverthorne processor is due for release around the same time. The chip is billed as an inexpensive, power-efficient processor that's ideal for ultraportable and handheld computers. Silverthorne is Intel's first chip designed for this product segment and will be the heart of Menlow, a chip package that pairs a processor with the company's Poulsbo chipset.

The conclusion that Isaiah processors may outperform Silverthorne is based on the relatively small amount of information about Intel's chip that has been released. Most importantly, it assumes that Silverthorne and a related processor called Diamondville, designed for low-cost computers, use an in-order processor architecture instead of an out-of-order architecture.

An in-order processor is similar to a factory with a single assembly line. The chip can only work on one operation at a time, and other operations must wait for the assembly line to clear before they can be processed. An out-of-order processor, like Isaiah and Intel's Core 2 chips, is equivalent to a factory with multiple assembly lines where different operations can be processed simultaneously.

Other factors also come into play. Silverthorne likely has a substantially smaller cache than Isaiah processors -- which have 1M byte of level 2 cache -- and could use a slower front-side bus, giving Via's chip an additional edge, Henry said.

Silverthorne's performance will also be constrained by business considerations. "They've got to protect the high-end money makers in the Intel product line," Henry said.

"You don't want to make Silverthorne too good and you don't want to make it possible for someone to use a Silverthorne instead of a mobile Core 2," he said.

Intel declined to answer detailed questions about Silverthorne's specifications and architecture, and it's possible the processor may confound Via's expectations when released. A true comparison of performance won't be possible until both chips are released and can be benchmarked by independent observers.

"It's very difficult to make an assessment given that Intel hasn't made a full disclosure on what Silverthorne is," said Dean McCarron, president of Mercury Research, a market research firm that tracks the microprocessor market.

But there are signs the two chips could be closely matched.

"The description of the two components, both Silverthorne and [Isaiah], that we know to date would seem to put them in the same general class," he said, noting that some versions of Silverthorne and Diamondville are expected to ship with two processor cores, while others will have a single core, like Isaiah.

"From what has come out, Silverthorne is rumored to be an in-order machine," McCarron said. "But we haven't actually seen parts yet, and it's certainly possible that particular rumor might not be correct."

Intel clearly aims to partition its product line and there will be a "gap" between Silverthorne and the Core 2 product line, McCarron said, noting this gap could be a difference in processor performance or architectural restrictions that limit the features and capabilities offered with Silverthorne.

"It's very safe to say that the Silverthorne products will be positioned in such a way that they would not threaten products above them in the product stack that Intel has," he said.

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