Intel works to cool down Xeon

High operating temperatures on Intel's top chip--its 400-MHz Pentium II Xeon processor for sophisticated servers--are related to recently reported performance glitches as well as the delay of the 450-MHz version of the chip for four-processor servers, according to sources close to company. The problems occur when four of the chips are used at once in a server.

Solving temperature problems is crucial in high-end servers because excess heat can cause data error problems. Servers containing four processors are some of the most powerful Intel-based computers on the market today and typically used to run critical database applications.

Intel is performing extra thermal testing on the chip to get around the problem, said an Intel spokesman, but the company may redesign some of the circuitry on the chip to cure it. (Intel is an investor in CNET: The Computer Network.)

"When the speed goes up, the possibility of errors increases," said one source in the server community about Xeon in four-processor configurations.

Xeon was initially designed to run at a maximum temperature of 75 degrees Celsius, according to sources. While a 75 degree thermal ceiling does not create problems for one- and two-processor systems, testing showed that it could affect a crucial function, called error correcting code (ECC), in four-processor systems. The 75 degree threshold does not cause the error per se. The lower temperature, however, prevents it from manifesting.

Intel has now lowered the threshold to 65 degrees per chip for these servers. Intel is meeting the goal by screening the chips through additional tests. But this is likely only an interim solution. To increase the number that pass the tests, Intel is likely to change some aspects of the design of the chip, several sources said.

Xeon carries higher profit margins than comparable Pentium II chips. Screening means a lower number of acceptable number of chips and, right now, four-processor Xeon servers are in short supply.

"Dell has a four week backlog of them," said Ashok Kumar, semiconductor analyst at Piper Jaffray.

The Intel spokesman would not comment on future product fixes but said, historically, Intel has corrected such problems as an ordinary part of improving the manufacturing process.

Computer makers declined to comment on Xeon's heat dissipation, but said that the effect on their server designs would likely be minimal. Some sources, however, added that Intel has requested vendors to beef up their insulating systems.

IBM, Compaq Computer and Dell Computer, for instance, stated that the thermal envelope on their respective servers fit well within the recommended design specifications from Intel. In other words, their servers contain enough fans and cooling features to keep the Xeon chip as designed now well under 65 degrees Celsius.

While four-processor Xeon servers, as designed now, may fit within the prescribed thermal envelope, Amir Ahari, server analyst for International Data Corporation points out that Xeon is one power hungry chip.

Server manufacturers have essentially doubled the size of the power supplies they have put into their Xeon systems. The power supply constituted about 5 percent of the budget of a four-processor 200-MHz Pentium Pro server. Now, the power supply takes roughly 10 percent of the budget. This additional power requirement forces server makers to build in more internal real estate and, of course, even more cooling systems.

"The bigger a system gets, the more heat it generates," he said, jokingly adding: "The key question is how to build a server that does not become the size of a mainframe."