The Incredible Shrinking Apple A5
Don Scansen posted on March 13, 2013 | 4314 views

Does Apple have a huge following? Can a new Apple product spark its own news cycle? Does the frenzy leave time for fact checking or sober thought?

Ah, we were doing so well until that last question.

A recent AnandTech software analysis suggested that the new generation of Apple TV would contain the third generation iPad’s A5X chip, rather than the single-core A5 used in earlier Apple TV units. This prompted MacRumors to tear into the latest Apple TV as soon as it hit retail.

Image source: Chipworks

MacRumors discovered that, while the chip had been given a new part number revision, it was still unquestionably an A5. They also noted that the DRAm was no longer stacked in a package-on-package configuration, but instead had instead been given its own spot on the logic board. Furthermore, this new A5 was significantly smaller than its predecessor. The new chip dimensions were approximately six by six millimeters, just over half the size of the old A5.

That much was confirmed.

This would probably have been unremarkable if it hadn’t happened to coincide with a string of recent rumors that Apple was changing chip manufacturers from Samsung to TSMC. Since the new chip appeared to have been shrunk down from 32 nms to 28 nms, and Samsung’s 28 nm processor had yet to enter production, MacRumors speculated that this might be the rumored TSMC-manufactured chip after all.

Naturally, this being the internet, all you have to do is speculate about a possibility and someone else will immediately start reporting it as fact. The new 28 nm chip quickly became the smoking gun that Apple had, in fact, switched manufacturers. It was a juicy story with just one small problem: it wasn’t true.

Chipworks performed an independent teardown, but went much further, cross-sectioning the device to look at the manufacturing process. Most notably, they discovered that the new chip wasn’t a shrink of the old design at all. It was still a 32 nm chip, and one most definitely manufactured by Samsung.

So, wait, if it’s not a 28 nm chip, then how’d it get so small? The answer might lie in Intel’s famous “tick-tock strategy,” which would first migrate an existing design to smaller process geometry – a tick – and then introduce new microarchitecture designs on a mature process technology – the tock. Since new designs are typically more complex, the mature process chips tend to be larger. So what does this tell us about Apple?

Apple is demonstrating its own tick-tock cycle, and the new A5 is a tock – a very small tock. Considering that the new design is 45% smaller, the real scoop will be when someone finds out just what functionality Apple chose to sacrifice... and why.

If you want to read more about the topic (and are not put off by shameless self-promotion), a recent perspective on Apple’s chip strategy can be found here.

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