IBM: Give Frequency Its Due

SAN FRANCISCO — In an age of multithreaded multicores, is frequency irrelevant? Intel Corp. seemed to answer in the affirmative when it announced a "right-hand turn" in architectural philosophy five years ago. But in a Power microprocessor being readied for a line of servers, IBM Corp. makes a case for pushing performance by pushing frequency.

Intel group vice president Pat Gelsinger announced Intel's right-hand turn at the 2001 International Solid-State Circuits conference, saying the company would keep power consumption flat by de-emphasizing megahertz and moving to dual-core designs with multiple threads. Sun Microsystems Inc. has taken a similar tack.

But at last week's ISSCC here, IBM threw down the gauntlet on frequency. IBM design engineers delivered three papers describing the pending Power6 microprocessor, aimed at the company's own pSeries servers. While the currently shipping, dual-core Power5+ design is in the 1.9-GHz range (and heading higher soon) on a 90-nanometer process, the 65-nm Power6 will debut in the 4- to 5-GHz range when servers begin shipping next year, said Mark Papermaster, IBM's vice president of technology development.

"We don't want to be blind on frequency," Papermaster said. "Otherwise, you will go right out of the thermal envelope of the data centers. But there still is a relationship between frequency and performance."

IBM's "megahertz burst" comes at a time when Intel has "taken its foot off the gas," said Rick Doherty, director of The Envisioneering Group (Seaford, N.Y.). "Intel has thrown in the towel," Doherty said. "They've stopped trying to get past 3.5 GHz."