IBM this week confirmed it is running the first working prototypes of its multi-threaded multi-core Power5 processors in its labs.

The Power5 chip will appear in some high-end server products starting next year. It is the next generation of IBM's PowerPC-based Power4 chip, on which Apple's G5 processor (which IBM calls the PowerPC 970) is based.

Discussing the Power5, IBM director of technology assessment Joel Tendler said: "We've already booted AIX, Linux and OS/400. We're deep in the middle of test cycle."

Symmetric everything When it ships, the Power5 will have a clock speed "slightly better" than 2GHz, and some "slight increases" in memory cache size over IBM's current Power4 processors, according to Tendler. But 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 as far as applications are concerned. This can improve the performance of some applications by as much as 40 per cent, Tendler said.

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

First to the punch "IBM was the first guy to do multiple cores on a chip, and Intel was the first guy 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 guy on the street to do that."

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 performance enhancements in the 20 per cent to 40 per cent range, Brookwood said.

Low power, slimline, low heat The first Power5 chips will be based on 130 nanometer process technology, meaning that the smallest features on these chips will be 130 billionths of a meter wide. In 2005, IBM will go to a 90 nanometer process, Tendler said.

IBM is also developing some dynamic power management features that will help the chips generate less heat, Tendler said.

Looking beyond the Power5, IBM's Power6 processor is expected to appear in 2006, he said.