Anticipating the ever-increasing computing demands of tomorrow’s mobile devices, chip makers are rolling out compact designs for processors that boost performance while drawing less battery power.
Designing processors for mobile devices requires more than simply reproducing desktop computer architecture in a smaller device. The tinier transistors get, the more electricity they leak, a killer for battery-powered devices. To address this problem, Intel has incorporated better insulating materials into its current generation of chips, and IBM’s chips will soon have a honeycomb design with empty spaces–because a vacuum is the best insulator of all.
Another strategy is to package multiple processing units on the same chip, a technology called multicore computing. Instead of, say, a single power-hungry two-gigahertz chip, two energy-efficient, one-gigahertz cores could deliver the same performance. But programming multicore processors effectively can be tricky (see “Multicore Processors Create Software Headaches”).
Packaging specialized systems with a general-purpose core can also be a way to boost performance for specific mobile applications, such as handling multimedia. Apple used this approach for its iPad tablet computer, creating a custom chip called the A4 to power the device. Qualcomm, Intel, and IBM are each taking this idea a step further by working on designs for three-dimensional chips with multiple layers of circuitry. These designs save energy by shortening the distance bits must travel between, for example, the processor and a memory chip (the longer the path electrons must travel, the more are lost to heat). Qualcomm expects to have such chips in products next year.
Keeping tabs on what a processor is doing (or not doing) is critical to extending battery life. This summer, Intel will release the next generation of its mobile Atom processor, which will use a third to half as much power as a conventional chip when it’s active and just a 50th as much power as when the device is idle.
In the short run, the drive to boost processor performance while saving energy will mean smart phones, netbooks, and tablets that work better and run longer on a single battery charge. And high-performance processors that require less energy may also change the way mobile devices are powered. The trickle of energy produced by a solar cell, or a piezoelectric device that converts the biomechanical energy of walking into electrical current, can’t do too much for today’s gadgets. But future mobile processors might get a significant boost from such energy sources.