Core Wars - What Will Power The iPhone 5?

While Samsung and Apple once again spin up their respective Lawtron 5000s and indulge in another multibillion-dollar game of rock-em, sock-em Lawyerbots, it will hardly have escaped readers’ notice that a new iPhone is now generally expected to be launched on or around 12 September – incidentally, the anniversary of Kilby’s first printed circuit.

Image via CrunchBase

And, unless something unexpected happens, that phone is likely to be toting a Samsung-made processor. Currently, the rumor mill is tending towards the idea that the iPhone 5 – or, realistically, the “new iPhone”, dementedly confusing as that may be – will be powered by a quad-core “A6″ processor.
Which is to say, a quad-core processor of the kind seen in the Exynos 4 chips currrently sitting in international, non-LTE versions of the Samsung Galaxy SIII.
Core envy?
On the one hand, this would certainly put a lot of oomph behind the iPhone. On the other, Apple has never been overimpressed by raw power when it comes to processors – the history of Apple in the modern age, in fact, has been one of competitors laughing at their underpowered spec all the way to the retail stores and carrriers. Where the laughing suddenly stops.
Further, the “new iPad” launched with a dual-core CPU, the A5X – along with quad-core graphics, to create a balance of performance for regular use and graphical power for gaming. Traditionally, new processors have arrived on the iPad and then, after extensive user testing, squeezed into the shell of the next model iPhone.
So, the current iPhone 4S shares its A5 processor with the iPad 2 (the old new iPad), and the iPhone 4 took its A4 processor from the iPad (the old old iPad). By that logic, the A5X would fit neatly into the iPhone 5.
In the iPad, the A5X’s extra power is primarily put into keeping that big, bright and beautiful 2,048×1,536 pixel screen up and running. Assuming that the iPhone 5 does indeed have a 4-inch screen (or something between a 3.95 and 4.08-inch screen) and retains the current pixel density, that makes an 1136×640 screen. Which gives plenty of headroom to play with the A5X’s power consumption and heat generation to create a high-performance dual-core phone chip.
Certainly, a high-end quad-core CPU is faster for general computing than a high-end dual-core CPU, all else being equal. But all else rarely is equal. Obligingly, Samsung have provided a handy comparison chart by shipping its first wave of Galaxy S III devices to the US with a dual-core Snapdragon S4 processor and internationally with a quad-core Samsung Exynos system-on-chip.
Quadrant benchmarks for general computing topped 5,000 for both, and it was only graphically that the Snapdragon suffered, producing frame rates roughly half those of the quad-core S III.
Although Apple’s boast that the A5X was graphically four times as fast as the quad-core NVIDIA Tegra 3 at the new iPad’s launch was made without detailed supporting evidence, subsequent testing did suggest that its two-core central, four-core graphics model produced around the same frame rates on a device with considerably higher screen resolution.
Clocking off
So, neophilia aside, is there a good reason to push an as-yet-unreleased quad-core A6 processor into a notional iPhone 5? Tweaking the graphical oomph of an A5X processor to reduce power demands would leave a very capable chip for a phone – phones, after all, not generally being expected to deliver the same sort of gaming experience as tablets.
There is also a financial argument. iPhone users – to generalize – tend not to care too much about the clock speed of the processor inside their device, as long as the device works. And, by the same token, Apple have managed to maintain the value of ageing hardware – to carriers and consumers – through their software update roadmap.
Very few users toting an iPhone 4S have complained that when they shake it they can only hear two cores rattling inside. Reports of descent into HAL-like hebescence in Siri have been the cause of more upset. In particular as we move to the Cloud, software optimization and back-end processing are going to be more important than pure processor grunt.

 (Image credit: AFP/Getty Images via @daylife)

And Apple would not be alone in sticking with dual-core – Intel‘s Atom Z2460 processor has a single core and is currently sitting in an exploratory set of inexpensive but solidly-performing Android phones, and its successor, the Z2580, will be dual-core.
Four play
The case for the A6? Obviously, it would provide a real break in technology between the iPhone 4S and the iPhone 5. It would allow Apple to claim core-to-core parity (or, this being Apple, superiority) with the current and coming wave of Android phones, represented for example by the Exynos in the Samsung Galaxy S III and the NVIDA Tegra 3 in the HTC One X.
And it would keep the awkward combination of hug and boxers’ clinch Apple and Samsung have developed going, potentially while Apple looks for another supplier able to match its incredible hunger for processors.
Taiwan Semiconductor Manufacturing Company has, of course, been checking its makeup and casting interested glances for some time, and rumors that it had secured the contract to make Apple’s A6 chips started back in September 2011. However, it has its own challenges with its 28nm fabrication technology.
Conclusion
There seems to be an emerging consensus on the outside of the next iPhone model – one which will no doubt be proven wrong in all sorts of exciting particulars when the thing is launched. But a 4″ screen, a wides-but-retina display and a new dock are all reasonably safe bets
The same accepted wisdom is increasingly tending towards a quad-core processor, but many of the reasons given have as much to do with how technology journalists and phone enthusiasts think than how Apple thinks, I suspect.
In either case, logic suggests a 32nm die size (as seen in the last iteration of the A5 chips found in the updated iPad 2 and Apple TV, and the quad-core Samsung Exynos), with commensurate power savings – a handy thing to have when shifting from a tablet’s battery space to a phone’s.
And the iPad Mini we’ve heard so much about? Well, that’s another story…