Intel’s Atom was once the Rodney Dangerfield of the processor world. It just didn't get no respect. The first Silverthorne-based Atoms were little single-core affairs that dipped into sub-1 W territory, but required a System Controller Hub that took platform power closer to 5 W. More capable versions from the Diamondville family bumped consumption higher still—all the way to the strange pairing of Atom and the 945GC chipset, which used more than 22 W on its own.
Not surprisingly, then, we haven’t published a lot of flattering coverage on Atom (I think the last time I even bothered with an Atom-based desktop was for Intel’s Atom D510 And NM10 Express: Down The Pine Trail With D510MO in 2009). Even today, five years after expressing its intentions to compete against ARM-based SoCs, the industry continues questioning Intel’s ability to deliver ample performance at power targets low enough to facilitate compelling tablets and smartphones.
Methodical progress compelled us to reconsider Intel’s efforts last year, though. Sixteen months ago, one of our writers went underground and made the bold prediction that Intel will overtake Qualcomm in three years. And that was when Intel didn’t have a single phone design win. The analysis was predicated on Intel’s ability to deliver a performance-competitive CPU based on 32 nm manufacturing and in-order execution, knowledge of the company’s manufacturing roadmap, and anticipation of a forthcoming out-of-order architecture.
Well, the details of that design, already known as Silvermont, become public today. And if the Atom processors based on Silvermont can do everything Intel says they can, then we won’t even need granular measurements like the ones we collected for ARM Vs. x86: The Secret Behind Intel Atom's Efficiency to quantify the company’s efficiency story compared to its ARM-based competition.
If you’ve followed the Atom family’s evolution, then you know that Intel hasn’t modified its fundamental microarchitecture in five years. Yes, it made a shift from 45 to 32 nm manufacturing. But the cores themselves—code-named Saltwell at 32 nm, but based on the original Bonnell design—continue to employ in-order execution, clearly favoring low power use at the expense of performance.
With Silvermont, that changes. We’re now looking at a more complex out-of-order execution engine largely enabled by a transition to 22 nm manufacturing. This isn’t a “see you again in five years” introduction, either. Intel is committing significant resources to dramatically accelerating development of its “light” architecture, promising yearly refreshes (the first of which will be Airmont at 14 nm, extending Intel's manufacturing advantage beyond the lead it enjoys at 22 nm).
In fact, Intel files all of the changes made to Atom into three categories: those that improve performance, others intended to achieve better power efficiency, and specific optimizations to the company’s process technology.