introduced the iPad mini yesterday and on the sidelines of its San Jose event Cupertino rolled out an updated full-sized iPad, powered by a new chip.
Although the mini was the star of the show, from a geek perspective the iPad 4 is a bit more interesting, as it features an all-new processor. Apple claim the A6X is twice as fast as the A5X, both in CPU and GPU performance.
It’s a massive performance boost, especially given the fact that the chip still appears to be A9-based and feature the same graphics. Of course, the A6 is a lot more optimized than the old A5 chip and it also clocks higher. The A5 in the iPhone 4S runs at 800MHz, while the A6 runs at 1200MHz. The A5X is clocked at 1GHz, so the A6X is probably clocked somewhere around the 1400MHz or 1500MHz mark. The 50% clock boost and architecture optimization would explain the twofold performance boost, at least in the CPU department.
As for graphics, it’s really not clear what Apple did to get such a performance bump. Ars Technica
speculates that the A6X uses the same SGX543MP4 quad graphics, which seems logical as 6-series PowerVR cores are still not available. Since the A5X GPU runs at 250MHz, the one used in the A6X could be clocked at up to 500MHz, explaining the twofold performance gain.
Of course, a clock increase tends to have a very negative impact on efficiency, but Apple could afford to go with higher clocks, as it also moved to a new production process. The A5X is a 45nm part, while the A6X is stamped out in 32nm.