How Intel will get an x86 chip into the iPhone

Will it ever be possible to cram a full-feature x86 CPU into Apple's awesome iPhone? Ever since Intel revealed the eventual target for the Atom ultramobile computing platform was smartphones, that has been the burning question.

Indeed, Intel claims the next generation of Atom, known as Moorestown and due out later this year, will be 10 times more power efficient than the current Menlow platform. And now we've seen the first evidence that Intel might just pull it off.

Tucked away in one of countless labs at Intel's sprawling Hillsboro, Oregon campus, a group of engineers have been chipping away at the Atom platform power consumption problem. Intel isn't ready to publicly discuss the ingredients that will go into Moorestown's low-power secret sauce, but Paul Diefenbaugh – a man with epic title of Intel's Client Energy-Efficient Architect - gave us a demonstration of one key technology which, we reckon it is safe to assume, will likely make an appearance.

In a deep sleep

Laid out on a workbench is a development version of the current Atom platform, complete with a 45nm Silverthorne CPU and a northbridge chip. The key difference here is the ability of the tweaked northbridge to power down into a deep sleep mode, similar to the low power C-states of Intel mobile processors, whenever the system is idling.

Crucially, the technology is also capable of waking the chipset up extremely rapidly. Thanks to a power meter hooked up to a nearby laptop, we could see the modified chipset power down when the system was idle. But a quick jostle of the mouse brings the system back to full power with no perceived delay or sluggishness.

All in, Intel reckons that this new northbridge power gating technology alone improves overall platform efficiency in idle mode by 35 to 50 per cent. Given that typical smartphone usage patterns involve long periods switched on but not in use, that's an extremely handy power saving.

Still, it's obviously nowhere near enough on its own to reach the 10x improvement in power consumption Intel is claiming for Moorestown. But then Moorestown is a very different beast from Menlow in many other ways, too.

Most significantly, it features increased feature integration including an on-die memory controller and graphics core, all of which serves to reduce power consumption even further. Having said that, however, we've an inkling even Moorestown won't be quite efficient enough to find its way into iPhone-like devices, partly because it is fabbed using current 45nm process technology.

Instead, the holy grail of an x86 iPhone (or any truly pocket-sized smartphone with an x86 CPU) will have to wait for the first 32nm Atom processor. Codenamed Medfield and due out in 2010, this will be a true system-on-a-chip design complete with on-die I/O and storage controllers.

The Atom processor has soaked up some criticism for its relatively poor performance in netbook machines. But it's still in a completely different league for grunt than any chip found in current smartphones. If Medfield has what is takes, we could all be enjoying full x86 power in our pockets as soon as next year.

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