What Processor is the iPhone 3G S Running?

Which processor is in the iPhone 3G S? Odds are that it's an ARM chip, as the Samsung ARM 11 was the chip used by the previous iPhone 3G. But the real question is whether or not it's a chip from the PA Semi team that Apple acquired for $278 million in 2008.

The issue is the instruction set. Apple's iPhone OS is written for the ARM architecture, will be available for the iPhone 3G and the new 3G S; if Apple planned to move to a new processor architecture, the iPhone OS 3.0 would not straddle both phones. So we can assume that the 3G S is an ARM phone.

Unfortunately, Apple wasn't talking. I interviewed Bob Borchers, senior director of iPhone  worldwide product marketing, who declined to comment on the chip's speeds, architecture, which company designed it, or even if it was an ARM architecture. "Within the mobile space we're mainly talking about what you can do with it," Borchers said.

Linley Gwennap, principal analyst at The Linley Group, which covers the embedded processor market, said he doubts Apple and its PA Semi team had had enough time to develop a chip for the iPhone. "I would think it's a safe assumption that it's another ARM processor they're working with," he said.

But, Gwennap added, it's impossible to say with certainty which processor is inside the new iPhone, or which vendor it was purchased from. "I would guess it's another Samsung processor with a faster CPU," he said. "It's possible that they switched [vendors], however."

What we don't know, as phone analyst Sascha Segan points out, is what particular flavor of ARM chip it is. Is it a Freescale Cortex chip? A more prosaic ARM derivative, merely clocked higher? To my knowledge, PA Semi was never an ARM licensee.

My notes show that Apple's characterizations of the iPhone 3G S performance focused on four key"benchmarks": the ability to lauch messages (2.1 times faster than the 3G), loading SimCity (2.4 times faster), viewing an Excel attachment (3.6 times faster) and loading the The New York Times.

According to Borchers, those metrics indicate "real-world things that make a difference". The software's new voice control options and the ability to edit video on the fly are two other indications of the software's performance, Borchers said.

On the plus side, the new iPhone 3G S also includes substantially more battery life, as Sascha Segan captured with his camera in our liveblog story: nine hours of Wi-Fi time for the iPhone 3G S versus six hours for the iPhone 3G; thirty hours of audio versus twenty-four for the iPhne 3G; and twelve hours of 2G talk time for the 3G S versus ten for the older 3G. That seems to indicate a process shrink, or shrinks, as well as some improved power management capabilities.

One other bit of news: there is no 802.11n in the iPhone 3G S, according to Borchers.

A version of this story originally appeared on Gearlog.

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