Performance: Atom vs. ARM's Cortex A15

In our iPhone 5 review I included this crude diagram comparing the high level micro-architecture layouts of the current crop of mobile CPU cores. While most of the cores looked fairly similar, the one to really stand out is ARM's Cortex A15. A three issue, OoO core, the Cortex A15 was designed to put ARM in a completely new performance category.


For 2013, the Cortex A15 is expected to be the ARM CPU core of choice for the next wave of smartphone and tablet SoCs. NVIDIA's Wayne should integrate multiple Cortex A15s as well as competing solutions from Samsung and TI. Samsung's Exynos 5 Dual, found in the new Chromebook, integrates two ARM Cortex A15 cores running at 1.7GHz. As our first experience with a Cortex A15, I wanted to get a good idea for how it would compare to Intel's Atom. And now me comparing to the older Chromebook 500 makes sense. The Atom N570 in the older Chromebook is the closest approximation we have to the currently shipping Atom based mobile SoCs. There are a number of enhancements to the newer chips (particularly when it comes to power consumption), but the base core is very similar. It's clear that the Sandy Bridge Celeron based Chromebook is faster than this new Cortex A15 design, but how about the old dual-core Atom model?

As Chrome OS is built around the Chrome browser, our tests had to be largely JavaScript based unfortunately. The good news is that even given the nature of the benchmarks, we're able to get a good feel for performance between the two SoC platforms. Both systems were running the latest version of Chrome OS at the time of publishing.

Samsung Chromebook Performance Comparison
  SunSpider 0.9.1 BrowserMark RIABench Focus Tests Kraken
Atom N570 1.66GHz 1034.3 ms 152780 1968 ms 14229.5 ms
Exynos 5 Dual 1.7GHz 690.5 ms 217031 1192 ms 9733.2 ms

The Cortex A15 is fast. Across the board we're seeing a 40 - 65% increase in performance over a dual-core Atom. Although it's not clear how performance will be impacted as companies work to stick Cortex A15 based SoCs in smartphones with tighter power/thermal budgets, in notebooks (and perhaps even tablets) the Cortex A15 looks capable of delivering a good 1 - 2 generation boost over Intel's original Atom core.

The IE10 browser tests tend to agree with our JavaScript performance tests, although the CSS Maze Solver benchmark shows a huge advantage for ARM over Intel's Atom here.

Samsung Chromebook Performance Comparison
  IE10 Bubbles Test IE10 Fishbowl IE10 Maze Solver
Atom N570 1.66GHz 11 fps 5 fps 45 seconds
Exynos 5 Dual 1.7GHz 17 fps 8 fps 17 seconds

GPU performance is an even bigger advantage for the Exynos 5 Dual over Intel's old Atom N570 (GMA-3150 GPU). I ran three different webGL tests, each of which showed just how bad the old Atom GPU core was.

Samsung Chromebook GPU Performance Comparison
  WebGL Solar System WebGL Cubes (500) WebGL Aquarium (50)
Atom N570 1.66GHz 2 fps 10 fps 2 fps
Exynos 5 Dual 1.7GHz 22 fps 28 fps 38 fps

This comparison isn't really all that fair as the newer Atom cores use Imagination GPUs, although even then they are using relatively underpowered solutions compared to what Samsung is shipping on the Exynos 5 Dual.

The more relevant conclusions here apply to the CPU comparison. Next year Intel is expected to introduce its first new Atom core since the platform's introduction five years ago. The new architecture will bring an Out of Order execution core as well as a tangible performance increase. The question is whether or not this will be enough to fend off advances from Cortex A15 based designs.


The new Chromebook (left) vs. the old Atom based Chromebook (right)

In our Surface review I looked at Clovertrail Windows 8 tablet performance and put it a good 40%+ faster than NVIDIA's Tegra 3. If ARM's Cortex A15 is able to outperform Clovertrail by a similar margin, it could make the next generation of Windows RT tablets even more attractive. Keep in mind that we're looking at an older Atom platform here and not Clovertrail, so the performance deltas could shrink a bit.

User Experience & Usability Battery Life & Power Analysis
POST A COMMENT

149 Comments

View All Comments

  • garfnodie - Thursday, November 15, 2012 - link

    Let's see, Chromebook for $249, or Transformer w/ keyboard for $600. I'm guessing if you'r a broke college student who needs something simple, the Chromebook is looking pretty good. Reply
  • Myrandex - Wednesday, October 31, 2012 - link

    Eh instead of the Nexus 10 + keyboard, Microsoft Surface all the way! Reply
  • Krysto - Thursday, November 01, 2012 - link

    Why? I want a good high-res screen on my device if I'm going to $400, which is $100 cheaper and has the same amount of free storage as Surface. Reply
  • qwerty321 - Wednesday, March 20, 2013 - link

    Not for long. When PNaCl is stabilised, ChromeOS users will be able to install native software. Obviously not Windows API stuff, but then who in their right mind would use that garbage anyway? There's a few things in the Chrome store experimenting with NaCl (the early, non-portable version) now. Reply
  • Midwayman - Wednesday, October 31, 2012 - link

    I'm just a little shocked how how much the nexus 10 costs vs the chromebook. Clearly there is some price padding in the nexus 10 price. Reply
  • kllrnohj - Wednesday, October 31, 2012 - link

    How do you figure? The two share a similar SoC, and nothing else. In particular the Nexus 10 has that incredibly gorgeous 2560x1600 IPS display, whereas this Chromebook has a mediocre, off the shelf 1366x768 TN display. Given that there's only a $150 difference between the two, the screen alone easily accounts for most of that. Similarly, the N10 is a smaller device - cramming the same stuff into a smaller form factor is typically harder and more expensive. Reply
  • Midwayman - Wednesday, October 31, 2012 - link

    There aren't a lot of points of comparison with the Nexus 10 screen. Granted I'm sure the screen is more expensive, but similar size, similar SOC, same memory. Given the pricing trend with the nexus 7 and chromebook I expected a price around $50 less. Or at least to come with 32gb of memory for that price. I don't think $400 is a *bad* price, but it isn't as aggressive as I expected. I'm sure there will be a parts cost breakdown soon. Reply
  • Krysto - Wednesday, October 31, 2012 - link

    Nexus 10 is a high-end tablet. Chromebook is a pretty low-end laptop, in all regards. Reply
  • sna19703 - Wednesday, October 31, 2012 - link

    Get a Windows RT Tablet. Reply
  • kyuu - Thursday, November 01, 2012 - link

    Once they release one with a better SoC than Tegra 3 and a 1600x900 screen or better, sure. Reply

Log in

Don't have an account? Sign up now