Report: Apple to use Intel's Silverthorne chip in 2008

After holding off on the release of a faster iPhone because of concerns about battery life, is Apple really prepared to take a step backward with Intel's Silverthorne chip?

AppleInsider reported Friday that Apple has decided to use Intel's upcoming low-power Silverthorne chip in "not one but multiple products currently situated on its 2008 calendar year product roadmap." Silverthorne is Intel's latest push to capture the handheld/mobile phone market as part of a product concept called the Mobile Internet Device.

The report goes on to say that the most likely candidates for Silverthorne are a 3G iPhone and the Newton-like tablet computer that AppleInsider reported on earlier in the year. Based on what we know about Silverthorne, I think the subtablet rumor might make sense, but a Silverthorne iPhone is unlikely.

Intel plans to release more details about Silverthorne at the Intenational Solid State Circuits Conference in February, but we already know from the advance program, and from what Intel said about the chip last year, that we can expect Silverthorne to behave like a much smaller 2004-era Pentium M processor that consumes just a watt or two of power, compared with the 35 watts consumed by Intel's Core 2 Duo notebook processors of today.

But that's still not enough for a phone. According to several iPhone teardowns, Apple is likely using the Samsung S3C6400, or some special equivalent built just for them, in the iPhone. That chip is based on the ARM1176 core, which at 620MHz consumes just 279 milliwatts. That's running all-out, whereas most of the time you're actually going to be drawing much less power than that. Silverthorne, by contrast, will consume 500 milliwatts of power at minimum, and probably only when it's doing nothing in idle mode.

Those numbers just aren't going to work in a phone, especially an Apple phone, if the company really is so concerned about power consumption that it has held off on releasing a 3G iPhone until the power consumption of that modem improves. Those numbers could work, however, in something more along the lines of a powerful handheld such as the rumored "Return of the Newton" that was discussed earlier this year. Based on the concept designs shown by Intel last year for Silverthorne-era devices, however, this would be something much larger than a phone, more along the lines of a UMPC or a handheld gaming device like Sony's PSP.

Given the close relationship between Apple CEO Steve Jobs and Intel CEO Paul Otellini, as well as Otellini's commitment to low-power designs, I would not at all be surprised to see Apple and Intel hook up on a future mobile phone or sleek mobile computer. But I wouldn't expect to see it until at least 2009, when Intel releases a chip called Moorestown that is expected to reach the milliwatt operating power of current ARM designs. Some of the concept devices that Intel showed off as Moorestown-era projects looked an awful lot like the iPhone.

Apple had to design the OS X operating system inside the iPhone and the iPod Touch around the ARM instruction set, because there's really no other realistic option right now for smart phones. But it might be looking at the development resources needed to port all of its software (iLife, iWork, GarageBand, etc.) over to ARM, and balking at the amount of time and energy that would require. If Intel can deliver an x86 chip with similar/better power and performance characteristics to the chips built by ARM's partners, it could be a very attractive product, and that's the meat of Intel's sales pitch to the phone makers.

Of course, ARM's partners will be out with dual-core chips by then that could tilt the performance equation solidly in its favor, while staying within the same power envelope. We've got a long time to muse about that.