Microprocessors growing extra head

SANTA CLARA, CALIF. – For decades, computer performance has been driven largely by the increasing numbers of ever-smaller transistors squeezed into the machines’ silicon brains.

With each generation, speeds jumped and prices dropped.

Though the tiny switches built in silicon are the heart of the digital revolution, they can’t shrink forever. And in recent years, chip companies have struggled to keep a lid on power and heat — the result of some transistor components’ getting as thin as a few atoms across.