Intel's Power Play

Power efficiency: The Nehalem architecture features a power-saving control unit that monitors the workload of individual cores. It can shut down inactive cores and divert spare power to active ones.
Intel

Computing

Details emerge of a chip design that will make computers faster without draining more power.

Thursday, August 21, 2008
By Kate Greene

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A significant shift in the way that many future computers will handle data is being prepared by the world's biggest microchip maker. On Tuesday, at its Intel Developer Forum (IDF), in San Francisco, the company revealed further details of Nehalem, a more power-efficient chip architecture that will be at the heart of many future products. Intel disclosed power-saving features that promise to let servers, desktop, and laptops run faster without needing more power.

Rajesh Kumar, an Intel fellow and a key architect involved with developing Nehalem, described the tricks used to make the architecture less power hungry. Importantly, a new power-saving control unit on the chip itself has the sole task of monitoring the workload of each of the chip's individual data-processing units, or "cores." If only two cores of a four-core machine are active, for instance, the control unit will completely shut down the inactive cores and divert spare power to active ones. The unit can also moderate the speed and power consumption of each core independently.

In addition to moderating the manner in which the cores crunch data, Intel researchers considered the behavior of the transistors within each core. With Nehalem, these are made using so-called 45-nanometer technology. On this scale, the materials used to make the transistors tend to persistently leak electricity, even when they are shut off.

So, to further save power, Intel's engineers developed a way to shut off transistors when they aren't in use. "The concept is trivially obvious and has been around for decades," says Kumar, "but doing it was hard." It required developing new transistor technology to ensure that the switch had low resistance when it was on but an extremely high resistance when off.

Using the same amount of power, a Nehalem machine can throw more processing cycles at a problem. In simple terms, Intel says, Nehalem will enable high-end desktops to render 3-D animation almost twice as quickly as the fastest chips available today, making video games more realistic and bringing high-quality animation software closer to the masses.

Computing