IBM's juiced Power6 stomps poor, old Power5+

ISSCC At a time when rivals have given up on juicing their processors, IBM plans to crank the heck out of Power6. The dual-core chip due out by mid-2007 will come in "just shy" of 5GHz and flaunt double the performance of today's Power5.

"We are showing that we're really doing twice the speeds and feeds of Power5," IBM's chief engineer Brad McCredie told us in an interview at ISSCC. "As usual, I think we are out there leading the industry."

The leadership claim came easier back when IBM beat competitors to the dual-core arena with Power4. But here we are in 2007 with IBM still sitting on dual-cores and a chip once meant to ship in 2006. In addition, IBM plans to take Power6 beyond 5GHz, while the entire industry scales back on pure speed in favor of numerous lower power cores that can digest more software threads.

IBM scoffs at suggestions that it has misread the market with Power6. The company preaches balance, balance, balance with a processor that can crush single threads while keeping overall system power consumption low.

Evidence of IBM's system balance can be seen via the servers planned for Power6. For the first time, IBM will push Power6 into its blade server lineup, replacing PowerPC chips. IBM plans to craft a special low voltage version of Power6 "in the lower 4GHz range" for such compact boxes. Power6 will then scale all the way up to a 64-socket beast - twice the size of the biggest Power5-based system shipping today. [IBM also plans to ship one-core versions of Power6.]

"We are able to scale the design pretty well," McCredie said.

"We are putting dual-core up and down the product line," he added, making sure we were paying attention.

While Sun bangs on about software threads with its upcoming 16-core Rock chips, IBM maintains that a more balanced - now we're making sure that you're paying attention - approach makes sense at this time. Customers still need strong single thread performance, and IBM still needs to pummel competitors on benchmarks.

Tradeoffs? What tradeoffs?

At 5GHz, you might expect Power6-based systems to make their way into the office kitchen for egg sandwich cooking duty. That's not the case, according to IBM, which has added a number of power management features to the chip.

With Power6, you get double the frequency and double the bandwidth but the same power threshold as Power5.

Customers will also find new tools for controlling how much power a server consumes. Using IBM's management software, a customer can set a wattage threshold policy for a system. Additional tools provide customers with data on how much power their servers consume.

"If they have all this information, a lot of customers will actually find they do have power to spare," McCredie said. "They just needed to know where it is."

Power6 has tool for tweaking the voltage and frequency of the chip, depending on demand, and has a "nap" mode that can lower power consumption by up to 35 per cent.

Looking forward, IBM plans to slot Power6 into midrange systems first and then scatter the chip into lower- and higher-end boxes. It's also considering a four-core version of the chip once IBM moves to a 45nm manufacturing process.

"We are exploring those options," McCredie said. ®