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.