There's a lot of life still left in ARM's 32-bit technology. The Cortex-A9 design has powered Apple's iPhone 4S, Samsung's Galaxy S3 and many Android tablets. The recently unveiled follow-on A12, with up to four cores, is aimed at mid-range mobile devices emerging in late 2014 and 2015. It's 40 percent more power efficient than A9, and up to 30 percent faster, according to ARM. That means better performance and longer battery life in tablets and smartphones. [See "ARM targets $200 smartphones with new Cortex A12 processor"]
The much more power-hungry A15 is aimed at high-end mobile devices, and servers. Samsung's latest Exynos 5 SOCs in the Nexus 10 tablet and Galaxy S4 smartphone are based on the A15. Both the A12 and A15 can be paired with the physically smaller, less powerful, but hugely energy efficient A7, in what ARM calls a "big.LITTLE" configuration. The higher-end processor takes over compute-intensive jobs, but the lower-end chip saves power by handling less demanding tasks.
Not everyone is a fan of ARM's road map. "I have been bearish on ARM's Cortex A15, believing that it is too power hungry for the mainstream/performance smartphone lines that are so popular," writes Ashraf Eassa at SeekingAlpha. "While I suspect that ARM's intentions with the A15 was never to really power smartphones (or to do so via big.LITTLE), both big.LITTLE and A15 have proven problematic for these segments, as Samsung's Galaxy S IV (international edition) has shown."
Eassa argues that the S IV edition powered by Qualcomm's Snapdragon 600, which also uses the ARM instruction set with Qualcomm's custom Krait core, has "superior battery life and good performance characteristics."
As his comment suggests, Apple and other architectural licensees such as Qualcomm, Marvell and Nvidia, can innovate on their own. AnandTech's in-depth analysis of Swift concluded that Apple improved the core's memory performance, reduced data cache access latency, and possibly added a second floating point unit among other changes. The result is dramatic performance gains in some types of operations compared to the A9, apparently without a power penalty.
Apple undoubtedly is moving ahead with mobile 64-bit processor technology, so testing makes complete sense. But new processors take years to develop and the processor tests, if real, are not an indication of an imminent release, without more definite evidence.