IBM runs Power5 prototypes

IBM confirmed on Tuesday that the first silicon prototypes of its multi-threaded, multi-core Power5 microprocessor are now...

IBM confirmed on Tuesday that the first silicon prototypes of its multi-threaded, multi-core Power5 microprocessor are now running in its labs.

"We have already booted AIX, Linux and OS/400," said IBM director of technology assessment Joel Tendler. "We are deep in the middle of a test cycle."

When it is offered in IBM's pSeries systems next year, the Power5 will have a clock speed slightly better than 2GHz and a slight increase in memory cache size over IBM's Power4 processors, said Tendler.

The chip's major innovation will be the addition of symmetric multi-threading, a feature that allows a single processor to behave like a dual processor. This can improve the performance of some applications by as much as 40%.

IBM's symmetric multi-threading is similar to the hyper-threading technology Intel made available with its Pentium 4 processors, according to Nathan Brookwood, principal analyst at research company Insight 64.

"IBM was the first to do multiple cores on a chip and Intel was the first to do symmetric multi-threading on a chip," Brookwood said. "The next logical step is to do multi-cores with multi-threading and it looks like IBM with the Power5 will be the first."

Symmetric multi-threading keeps processors busier by letting them use clock cycles that would normally go to waste when a chip's cache is waiting for more information to be transferred from a computer's memory. It typically delivers a 20% to 40% improvement in performance, Brookwood said.

The first Power5 chips will be based on 130 nanometre process technology, meaning that the smallest features on these chips will be 130 billionths of a metre wide. In 2005, IBM will go to a 90 nanometre process.

Improvements to the AIX operating system planned for Power5 will allow users to turn the multi-threading feature on or off.

Users of high-performance or technical applications might want to run the new processors in single threaded mode, Tendler said. "There are cases when you do not run from memory so the only thing holding up execution is how fast you can drive the processor."

IBM is also developing dynamic power management features that will help the chips generate less heat. IBM's Power6 processor is expected to appear in 2006.

Robert McMillan writes for IDG News Service

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