IBM powers up processors

IBM expects to ship a Power5-based server this year.

Codenamed Squadron, the 64-processor p690 will debut mid-2004, sources say. Squadron was formerly known as Armada. A prototype is currently deployed, IBM claims, and IBM representatives talked about it at Stanford University’s Hot Chips conference last week in Palo Alto.

Power5-based processors will be used in IBM’s pSeries and iSeries servers as well as in its Enterprise Storage System array, also named Shark. Longer term, IBM will use it in its zSeries mainframe servers.

Architecturally the Power5 processor differs from the present Power4. IBM has added simultaneous multithreading, which allows two threads to run concurrently at full speed. Previous versions used hardware multithreading, which allowed single physical processors to be split into two virtual processors and run threads simultaneously, resulting in only a 20% performance increase. Simultaneous multithreading is known in Intel nomenclature as Hyperthreading – a single processor appears as two. Hyperthreading appears in Intel Xeon processors.

Additionally, in the Power4 processors IBM used single-threaded cores. The Power5 will use two threads per core, making for a more powerful processor.

The company will also use dynamic power in the Power5, which allows components of the chip to be powered down when they are not in use. Using this form of dynamic power management, Power5 chips will not run as hot and will use less electricity.

With the Power5, IBM is also putting the memory controller on the chip to increase performance. The company claims that with these enhancements Squadron servers will be as much as four times as fast as its Regatta servers, which are based on the Power4.

Further, IBM expects to build autonomic computing capabilities into the Power5, to allow software to shift jobs from processor to processor as demands change.

The Power5 processor will run AIX or Linux.

IBM previously said that more than 12,000 Power5 processors will be used in ASCI Purple, the supercomputer that will be deployed by the Department of Energy.