Here's your Apple A9 and A9X confusion thread

— 4:41 PM on September 9, 2015

We learned from today's announcements that Apple has produced a couple of new, high-end mobile SoCs for its iPad Pro and iPhone 6S products, and the company made some pretty serious claims about the performance of those devices. Let me outline for you what we know, and then it will be clear how much is missing.

First, the iPad Pro is powered by the A9X SoC. Apple says its CPU is as much as "1.8x faster" than the triple-core "Cyclone++" processor in the A8X chip onboard the iPad Air 2. That enhanced version of the Cyclone core was already one of the most potent mobile CPUs cores anywhere. The firm also claimed on stage that the A9X CPU is faster than 80% of the portable PCs shipped in the last 12 months, which seems like quite the assertion. GPU-wise, the improvements are apparently even larger: twice the performance of A8X and faster than 90% of the mobile PCs shipped in the past year.

That's not all. The A9X's memory bandwidth has purportedly doubled, as have its read/write speeds for flash storage.

The A9 chip that drives the new iPhones is similarly improved, with Apple claiming up to 70% faster CPU performance and and 90% faster graphics.

The A9 is said to be Apple's third-generation 64-bit processor, so it presumably has a further evolved CPU microarchitecture. I would expect the improved CPU core to process more instructions per clock cycle than prior generations, perhaps at higher clock speeds or with added energy efficiency.

The firm also revealed that the A9 chip is based on a "new transistor architecture," which is almost certainly FinFETs at 14 or 16 nm. The new process technology should allow for lower voltage operation, improving the SoC's power efficiency in ways that can be converted back into performance. That change alone could contribute a sizeable portion of the CPU performance gains.

Here's what we don't know: everything else.

The A8 SoC has two cores while the A8X has three. Has Apple maintained the same core counts in the A9 and A9X? Given the similar claims it's laying down about performance claims for the two SoCs, I would expect so, but the firm didn't say.

Critically, we also don't yet know how much RAM is in the new iPhones and iPads. The iPad Air 2 is the only iOS device of the the past generation with 2GB of RAM onboard, and I view 1GB of RAM as the single biggest weakness of the iPhone 6 and 6 Plus. I'd bet on 2GB in the new models, but I'm an optimist.

Then there's the bit where Apple says the A9X is faster than 80-90% of mobile PCs shipped in the past year. What is the basis for comparison there? I'm not talking about the CPU and GPU tests being used to measure, which are an utter mystery, but about the PC processors in question. Does Intel ship so many Atoms and Celerons that the A9X can eclipse such a large proportion of mobile PCs in performance, or is the A9X able to outperform some portion of the chips based on Broadwell and Haswell?

Apple has more money than God and may have spent a small slice of it building a world-class CPU architecture. But has it really caught up to Intel's big cores? Here's the thing: I dunno!

That's just the tip of the iceberg of ignorance we all, collectively, have about the new Apple SoCs. I expect some details will filter out today and in the coming weeks as the devices based on these chips get into the hands of the press and public. Feel free to post in the comments below as that process happens. Perhaps we'll learn something, or perhaps we'll just multiply our ignorance. Hard to say.

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