AnandTech has done its usual trick of analysing the hardware in great detail (hats off, chaps) and reports that the new Cyclone processor cores (which replace the A6’s “Swift” cores) have been “completely reworked”.
Apparently all three of Apple’s A7 devices use the same implantation of the chip too, codenamed S5L8960X. It’s running at the same dual-core, 64-bit setup with the same 1GB of RAM in the iPhone 5S and both new iPads. Allegedly the boost in performance on the iPad devices is down to more space inside the chassis, meaning better cooling and greater efficiency generally with a clockspeed difference of 1.3GHz in the iPhone and 1.4GHz in the iPad Air.
To keep heat and battery use in line, Apple seems to be throttling the chip at different speeds in different devices. The iPhone 5S will hit top speed on intensive tasks and then drop to 900MHz, while the iPad Air but only drops to 1.2GHz in similar conditions.
The nanometre technology in use is also making a difference on battery consumption. The A7 chip is 28nm compared to the A6X’s 32nm. According to AnandTech’s report, the iPad Air has some more intelligent battery saving tricks in play than previous models, able to tick over at relatively low wattage for less intensive tasks.