Among the expected changes to the next generation of iPad is an improved processor. Seeing as the original iPad had the A4 and the iPad 2 had the A5, it was logical to guess that the iPad 3 would have an A6. As it turns out, that’s not the case: a leaked picture of the iPad 3’s logic board (or what is claimed to be so) shows not A6, but A5X written on top of the chip.
In a way it’s totally inconsequential; not only is the naming scheme brand new and potentially arbitrary, but we barely understand what’s happening under the hood in the A5. A5X or A6, what difference does it make?
Well, here’s the thing. When teardowns of the A5 appeared, everyone was kind of disappointed at how little was revealed. Unlike the nearly off-the-shelf A4, the A5 is a truly custom-engineered chip, and Apple wasn’t going to let any secrets out of the bag. It has a huge amount of mystery silicon that could be dedicated to anything or, and this really is an option, totally unused. But the takeaway is that it was a truly new chip when it came out.
If we assume that any chip called A6 was going to be another “truly new” chip, i.e. built again from the ground up, it is a little optimistic to think that such a chip would be able to be designed and shipped so close on the heels of the A5. It’s much more likely that Apple would improve the existing chip with updated sub-components: a new graphics chip, an improved processor. Why do a total overhaul of a chip that’s performing perfectly well. The R&D is certainly being done, in order that Apple can stay competitive with more chip-focused companies like Texas Instruments and Marvell, but there’s no need to hurry it out.
There’s precedent for this, of course: Intel’s “tick-tock” strategy, which has been helping them dominate the CPU industry for a decade. They design a new processor, and then over the next year, move it over to the die-shrunk silicon and do a little housekeeping, improving and troubleshooting. Thus Core becomes Penryn, Nehalem becomes Westmere, and Sandy Bridge becomes Ivy Bridge. Apple doesn’t have the same resources or goals as Intel, but they must obey the same restrictions: designing a new chip architecture every year is (at this point) unnecessary, and besides that it’s unlikely Apple is capable of doing it. They’re already tick-tocking their hardware designs to make their industrial design work pay for itself a little better.
What’s the A5X, then? For one thing, and this isn’t a joke, it’s possible they called it the X instead of S because, as a commenter points out elsewhere, A5S looks like “ASS” &Mdash; these are the considerations that seem silly but when ignored, live forever in infamy. The specifics of the processor can’t really be speculated on, but it’s very likely that it’s more of a spec bump than a really big change. An improved processor — quad-core, dual-core, who knows; both are sufficient for the vast majority of iPad tasks and things like Infinity Blade and video decompression are better served by the parallel processing architecture in the GPU, not the serial architecture of a traditional CPU. So there will also be an improved GPU, vastly improved if you ask me, since it will have to drive 3D games at a monstrous 2048×1536 resolution, or at least handle the upscaling gracefully.
Supposedly we’ll find out in a couple weeks. Depending on what they announce, it could telegraph improvements to the next iPhone as well, so expect a hearty amount of speculation on that come early March.