ARM vs Atom: Intel's Newest Challenge

The ARM architecture offers several advantages when compared to Atom.

ARM has smaller die sizes than the Atom processors which gives ARM a cost advantage. Having been designed for use in space sensitive environments, the ARM core is smaller than the Atom equivalent. This is the case even though Atom is being manufactured on a more advanced process than most of the current ARM designs.

In addition, ARM is more highly integrated than Atom. Almost all ARM products for use in the mobile space are single chip SOC solutions. This offers a substantial size advantage over the current Atom solution which requires three chips and the upcoming solution (Moorestown) that is still a two chip solution. Atom won't offer a single chip solution prior to the advent of Medfield sometime in 2011. So Atom won't be able to match ARM for solution size or integration until somewhere between 1 and 2 years from now.

But the biggest advantage ARM holds right now is in power efficiency. Qualcom's Snapdragon processor is the poster child for ARMs high performance processors, so I'll use that as a reference point. The Snapdragon processor is reported to use 250-500mW under load at 10mW at idle. Atom's Moorestown, due out later this year, should use ~1000-750mW under load and ~35mW at idle. So ARM offers about a 2-3X power efficiency advantage over the Atom platform.

With all these disadvantages, one wonders what Atom can bring to the table.

First and foremost is sheer processing power. If you look at Intel's marketing around the LG GW990 from CES, you will see an emphasis on multi-tasking. ARM is closing the gap on responsiveness on single apps, but the x86 architecture that Atom is based on still seems to have more horsepower and allows you to do more things at once.

Another big advantage that Atom currently enjoys is the ability to run flash applications. However, Adobe is reportedly working with ARM to enable their processor designs to run flash applications. So this advantage is going to be short lived. It has helped Atom become the dominant netbook processor but it will not continue to drive future growth.

The last advantage that the Atom brings to the table is the ability to run Windows. By being able to run Windows, Atom brings a large software infrastructure to the table for any device it is installed on. But this advantage isn’t quite as big as it might seem at first glance.

The Atom processor was designed to be a “good enough” processor for basic PC tasks like browsing the internet, viewing video, etc. But it lacks the power to run large applications well. So while Atom may be capable of running x86 applications, the experience with many of them is poor. If the software doesn’t run well it is not much better than not running at all.

The use of Atom in small form factors further offsets the advantage of using existing software. Many of the current applications don’t fit these small form factors very well. This can be fixed, but requires that the code be modified to correct the problem. Having to modify the code for this purpose nullifies much of the advantage of being able to use the existing software.

Intel’s marketing along the software lines seems to have matured beyond the idea of basic software compatibility of late. They are placing a greater emphasis on cross platform portability. I believe that this is a more realistic assessment of the x86 advantage than focusing on the software because it focuses on one of the few real weaknesses of the ARM architecture.

ARM doesn’t manufacture chips, it sells licenses to use its architecture. Each licensee is free to modify the basic design to suit the licensee’s needs. This results in an ecosystem where the various implementations from different vendors may not be compatible with each other even though they are based on the same core architecture.

Systems built around the x86 architecture bring the guarantee of cross system compatibility. Not in the sense that you can move the software directly, but rather in the ability to link the systems together and transfer data between them. So by choosing Atom, you know you are choosing a device that will work and play well with your other devices.

In summary, ARM and Atom are rapidly converging to similar levels of computing power and energy efficiency. Within a few years I believe there will only be one key differentiator between the two architectures. The differentiator will be the ease with which you can move data between your various computing applications.

Due to the homogenous nature of the hardware infrastructure Intel is building I believe this gives them a substantial advantage. However, there is still a need for urgency on Intel’s part. If ARM becomes the entrenched incumbent architecture in this new space, it will take far longer for Intel to move Atom down into the smaller devices. I believe the x86 architecture, warts and all, will become the dominant architecture in personal computing devices. But if Intel doesn’t move quickly enough they will miss the initial growth curve and the resulting profits that come from riding that curve.

Edit: Cleaned up the spacing