IBM reveals Power6 details

IBM has revealed details of much-trailed Power6 processor, which is scheduled to be launched in 2007, at the International Solid-State Circuits Conference (ISSCC) in San Francisco. The key message is that it runs fast and cool, bucking the trend in the rest of the industry where the megaHertz wars have hit a brick wall because of excessive power demands and resulting heat generation.

Designed for servers - especially so now that there's no Apple to satisfy - the 65nm part runs at up to 5GHz, is built on silicon-over-insulator and other technologies, and includes a 64Kb L1 cache. It's reported to have an eight-way, set-associative design with a two-stage pipeline supporting two independent reads or one write per cycle.

Achieving the additional speed while keeping power and heat under control entailed going back to start and re-engineering the whole chip, according to Bernard Meyerson, chief technologist of IBM's Systems and Technology Group. He said that IBM had hit the limits attainable four years ago in terms of doubling the number of transistors and cutting power, and so had taken a holistic approach to chip design to produce the Power6.

According to one report, Meyerson said: "In Power6, we basically combined everything we could (throw) at it in terms of fundamental atoms and molecules all the way out to what we knew would be the software that would run on top of that system."

Dubbed the eCLipz (enhanced Core logic for iSeries, pSeries and z Series) project within IBM, the chip's designed to keep IBM ahead of Intel, AMD and Sun -- it's more than twice as fast as the 1.9GHz Itanium, for example - and allow servers to run faster while keeping within the same power envelope.

"There’s nobody looking at anything like this. We have a more highly integrated chip that is multi-core and we are increasing the frequency – we are turning up both knobs at once when the industry is going the other way and turning [the frequency] knob down," Myerson told the FT.

According to analyst Richard Doherty at Envisioneering, IBM has achieved 6GHz in the labs. He described the Power6 as the fastest chip so far, and likely to remain so "for some time".
The chip will first find its way into IBM's volume server lines such as the pServer and then iServer. According to one technical journal, it's unlikely to be simply plonked into Big Blue's zServer mainframes. Instead, the zServer's CPUs are likely to be spin-off designs developed alongside the Power6. IBM's iSeries chief scientist and co-developer of the Power CPU, Frank Soltis, told Techworld that IBM's mainframes are more likely to see a burgeoning number of specialised co-processors tuned for running Java, for example.