I keep coming back to it. The question keeps nagging away at me. What is Apple doing building up a chip division? Why has it spent money on ex P.A. Semi engineers? Why is it still advertising for chip engineers? What on earth is it up to?
The consensus amongst Apple-watchers seems to be that this has to do with the mobile side: the iPhone, iPods and whatever sundry network appliances make it out of the gates in the years to come. The desktop and server markets are just too firmly owned by Intel. Apple, having not so long ago come in from the IBM Power PC sphere where it had been getting dangerously far behind in terms of performance, would never be foolish enough to walk out of it and risk that happening again. Plus, Apple had to make a significant and presumably costly effort to port its software from Power to Intel, and would not soon countenance another such expense.
So on the mobile side, the iPhone has an ARM cpu (much criticised by Intel as being slow and lacking horsepower) and a couple of Imagination Technologies' PowerVR graphics processors (a geometry engine and a 3D accelerator). iPods also have an ARM based cpu; I'm not sure what gpu they have, if any.
Most commentators seem to think that this is all about adding unique features to Apple products, and reducing the amount that external chip suppliers know about Apple's technology. I think maybe it's also about taking out stuff that Apple don't need: currently they are buying in complete, general-purpose, mass-market, chips. For example the iPhone cpu, a Samsung device based on ARM IP, contains a "Jazelle" subsystem meant to accelerate Java performance on mobiles: since Java performance on iPhone has zero value for Apple, that's just so much wasted silicon, wasted money and wasted power.
It's possible then that Apple want to design their own chips. Now ARM technology can be licensed as IP, not just bought in as prebuilt chips. Apple could bypass Samsung and license ARM core IP directly. Exactly the same approach is followed by Imagination, so Apple could license the necessary PowerVR IP from them, and go on to design a single chip that incorporated not only ARM and Imagination cores but also their own, unique goodies. Even if all they end up doing is integrating into one or two chips stuff that they could have got elsewhere in several, the resulting savings in manufacturing costs (and more importantly, power consumption) would be well worth having.
This has to be far and away the most likely scenario, so it looks good for ARM and Imagination, less good for companies currently supplying the actual chips. Though Apple would undoubtedly farm out its chip making to a foundry, so perhaps one of its chip suppliers would benefit there.
Of course, a speculative post like this one wouldn't be complete without an absolutely outrageous coda. So, I'll go there. Pretty soon, Steve's very good friend Larry is going to have a RISC chip making business that I suspect he's not likely to really want. Apparently, Sparc chips can be implemented with an extremely low logic gate count — the same order of magnitude as ARM designs. A couple of weeks ago I wondered why SUN had never scaled Sparc down as well as up (the name stands for "Scalable Processor Architecture" after all). Perhaps Apple might be prepared to do that? Maybe not for the iPhone/iPod, but possibly for the tablet/netbook markets, the sort of space that Intel is aiming for with Atom, or even for the home server market?