ARM designs the chips used in most of the world's smartphones and tablets, including Apple's iPad and iPhone. The A7 will be its most energy-efficient chip design to date, ARM said at a press conference in San Francisco Wednesday. Samples are due next year, and the A7 will appear in entry-level smartphones by 2013, ARM said.

But the A7 will also be used in high-end smartphones alongside the upcoming Cortex-A15, as part of a that ARM calls big.Little. With that design, high-performance tasks such as gaming and video playback are performed on the more powerful A15 chip, while tasks that require less power, such as posting a status update or making a phone call, are assigned to the A7 to conserve power, ARM said.

By combining two types of core on the same chip, and assigning different applications to each depending on their requirements, ARM said it can resolve the conflict between the need for both higher performance and longer battery life. It will reduce power consumption by 70 percent for many common tasks, compared to mainstream smartphones today, it said.

It's a new approach for ARM but not an entirely new one for the industry. For example, Nvidia that its , code-named Kal-El, actually has a fifth core for performing tasks that require less processing power. It's the same in principle as big.Little, except Nvidia is using a Cortex-A9 design for all five cores, and it developed its own technology for keeping the cores in synch.

The A7 will be manufactured on a 28-nanometer process, ARM said. The more advanced process, combined with architectural improvements, makes it one-fifth the size, with one-fifth the power consumption, compared with today's Cortex-A8 processor, ARM said. But the A7 will still give a 50 percent performance boost compared to the A8, according to ARM.