August 27, 2013, 2:09 PM — Bloggers are speculating that a 31% boost in speed for Apple's not-yet-announced A7 processor is related to still other speculation that Apple will introduce a 64-bit chip architecture in the next iPhone. But there's not much of a foundation for any of the conjecture.
In fact, ARM Ltd's first 64-bit processor cores for the mobile market are not expected to appear in very high-end smartphones and tablets until sometime in 2014. Shifting from a 32-bit to a 64-bit chip instruction set, by itself, yields only a relatively small performance boost, of 8 percent to 10 percent, according to James Bruce, lead mobile strategist, ARM, Ltd.
Most smartphones today run processors based on the ARM instruction set and ARM-designed processing cores, which are actually manufactured by various silicon foundries. As an architectural licensee, Apple no longer relies on ARM's cores: with the dual-core A6 system-on-chip (SOC) in the iPhone 5, Apple introduced its first custom-designed core, dubbed Swift. For some highly technical detective work on Swift, see the in-depth iPhone 5 review at AnandTech, which begins its analysis of Swift here.
Bruce did not comment on Apple's plans. He did say that ARM partners will be incorporating the first 64-bit ARM mobile processor, the Cortex-A53, into 2014 smartphones. "But they'll just be running 32-bit software," Bruce says. The A53 is intended as a follow-on to the 32-bit Cortex-A7, with improved efficiency, according to Bruce.
The new wave of 64-bit speculation began Sunday with a single tweet by Fox News anchor (sometimes incorrectly described by bloggers as a "reporter") Clayton Morris: "Sources are telling me the new iPhone's A7 chip is running at about 31% faster than A6. I'm hearing it's very fast."
Past generational shifts in the A series processors have led to a doubling in performance, according to Apple.
Morris didn't mention 64-bit. But Mark Gurman did in a 9to5Mac.com post suggesting that the faster speed noted by Morris may be due to the use of a 64-bit architecture.
In keeping with rumor convention, Gurman refers to the next iPhone as the iPhone "5S." It is widely expected to be announced Sept. 10.