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A software emulation technique used inside Transmeta's Crusoe processor that hinders the performance of the low-power chip could be the reason some top PC manufacturers are falling back from commitments to ship Crusoe in future portable computer offerings, analysts say.

Compaq on Tuesday was the latest computer maker to adopt a wait-and-see strategy concerning the Crusoe chip. (See "Compaq Rejects Transmeta's Crusoe Processor.")

Seven days ago, IBM canceled its plans to ship the Crusoe processor in its ThinkPad 240 model laptop computers. (See "Transmeta Extends Its Battery's Life, But What About Its Own?")

Officials for Compaq, which invested $5 million in Transmeta earlier this year, say they will continue to follow Crusoe's progress and consider it for use in future products.

While Compaq officials wouldn't delve into specifics as to why the company wants more time before committing to a Crusoe-powered system, one Compaq source says certain "software interactions" having to do with the Crusoe chip did play a part in Compaq's decision.

Initial Price for Smarts

Crusoe, which officials for Transmeta claim can run complicated operating systems such as Windows 2000 while consuming as little as 1 watt of power, uses a software emulation technique to process instructions. This technique, also known as software morphing, lets the Crusoe processor actually read incoming command lines at the software level, rather than reacting strictly from the hardware level, like an Intel-based processor does. (See "Crusoe: A Tool for the Road.")

The advantage to software emulation, according to Transmeta, is a smarter processor that company officials agree operates more efficiently on repeated commands that the chip has already translated. But it is the initial translation that creates an extra step for the Crusoe processor, and this step apparently robs Crusoe of needed performance.

A source close to IBM says Crusoe's need to translate incoming command lines creates an unacceptable degradation in performance.

"Essentially, [software emulation] can be likened to a memory cache," agrees Dean McCarron, an analyst with Mercury Research. "It takes longer when you first access it, but it's quicker the next time, and there is no way around that."

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