ARM Vs. x86: The Secret Behind Intel Atom's Efficiency

Windows 8 Gestures: Latency And Power Consumption

Microsoft Surface

Delay (ms, Lower is Better)Frame Rate (FPS)Platform (W)CPU (W)GPU (W)Memory (W)Panel Backlight (W)Everything Else (W)
Bing Maps (Split-Screen / Pinch)133.3386.061.070.970.770.982.27
Bing Maps (Split-Screen / Drag)12545.65.800.800.760.960.982.30
Bing Maps (Split-Screen / Flick)17557.65.650.980.920.600.992.16
Wikipedia (Split-Screen / Pinch)158.355.35.280.970.750.470.992.10
Wikipedia (Split-Screen / Drag)183.357.24.920.700.720.460.982.06
Wikipedia (Split-Screen / Flick)183.3604.890.660.700.490.992.07
Acer W510

Delay (ms, Lower is Better)Frame Rate (FPS)Platform (W)CPU (W)GPU (W)Memory (W)Panel Backlight (W)Everything Else (W)
Bing Maps (Split-Screen / Pinch)83.333.85.500.760.500.541.242.47
Bing Maps (Split-Screen / Drag)91.742.45.360.720.550.551.252.28
Bing Maps (Split-Screen / Flick)116.756.24.960.580.450.491.232.22
Wikipedia (Split-Screen / Pinch)75.053.75.070.820.340.441.282.19
Wikipedia (Split-Screen / Drag)15059.24.760.640.310.441.262.10
Wikipedia (Split-Screen / Flick)83.356.54.530.590.320.421.261.94


Finally, we get a glimpse of power consumption during touch-based gestures using the Windows 8 UI on Bing Maps and Wikipedia using a split-screen configuration. This is the sort of thing you'd never be able to quantify without fancy equipment, but would almost certainly notice using both devices one after the other.

Not to belabor the point, but look at the memory controller numbers again. The Atom’s power consumption remains stable, regardless of the workload, whereas the Tegra 3’s consumption increases alongside complexity. Acer's W510 actually uses more power than the Surface elsewhere. But because its CPU, GPU, and memory controller are more efficient, total platform consumption is lower than Microsoft's.

In the upcoming piece on Acer's W510, we'll discuss some of the optimizations Intel made to its memory controller specifically to improve touch responsiveness at the expense of synthetic benchmark performance. In this case, the first column tells us that the delay for detecting a gesture is shorter (faster) on Acer's tablet than Microsoft's every single time. The best-case scenario for the Surface is still slower than five out of the six gestures tested on the Atom. However, the Surface yields generally-better frame rates. If you look at a Wikipedia pinch, the Atom allows the frame rate to drop 3%, but yields a latency that's twice as fast. The Surface is 11% faster in a Bing Map pinch, but incurs a delay 60% higher.

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  • Excellent! Was wondering about this for some time. Also made the mistake of thinking Intel was behind in the mobile space... Well done Toms.
    17
  • of all the ARM types, u took one of the weakest one? I like to see the numbers vs Qualcomm krait and Apple's A6
    16
  • And the Chromebook with an A15. We're looking at several other SoC's but what's empowering is how simple math can help you look at efficiency.

    But it's Christmas Eve, and sometimes there are more important things than running benchmarks and soldering wires to SoCs. ;)
    14
  • Other Comments
  • Excellent! Was wondering about this for some time. Also made the mistake of thinking Intel was behind in the mobile space... Well done Toms.
    17
  • I'll be very interested to read the Cortex A15 follow up. From what I gather, if compared on the same lithography the A15 core is much larger than the A9, which likely means more power, all else being equal. It brings performance up to and sometimes over the prior generation Atom, but I wonder what power requirement sacrifices were made, if any.

    I'm thinking in the coming years, Intel vs ARM will become a more interesting battle than Intel vs AMD.
    3
  • @tipoo, we're not going to hang our hat on it just yet (until we run the numbers ourselves), but A15 runs hot, which is what we hint at in our article.
    3
  • tipoo I'm thinking in the coming years, Intel vs ARM will become a more interesting battle than Intel vs AMD.


    I was until I saw the numbers. Intel spent $8.4 billion in 2011 ($6.6 billion in 2010 and $5.7 billion in 2009) on R&D - http://www.intc.com/intelAR2011/business/research/ - while ARM isn't worth $1b. It may take a few years but Intel are seriously massive, they'll soon be the go to guys for mobile. Plus (according to rumours) with Haswell focusing on power saving, it could be a big leap forward.
    11
  • AlanDang@tipoo, we're not going to hang our hat on it just yet (until we run the numbers ourselves), but A15 runs hot, which is what we hint at in our article.


    I'm guessing the same thing. So far we've only seen it in a tablet (Nexus 10), and even that with its 10 inch tablet sized battery didn't last particularly long. ARM has the distribution advantage right now, but I think once Intel gets its foot in the door it will be the 900lb gorilla in this market as well.
    5
  • ARM isn't just ARM holdings, it's nVidia, Samsung, and Qualcomm just to name a few of the heavy hitters. And it should also be noted that even if your SoC is better, if the OEM integrating it is incompetent, it won't matter. I'm certain more Surface RT devices have been sold compared to the Acer W500 because it had better availability, a stronger marketing campaign, and overall is a far more solid device. Don't miss the forest for the trees.
    0
  • blubbeyI was until I saw the numbers. Intel spent $8.4 billion in 2011 ($6.6 billion in 2010 and $5.7 billion in 2009) on R&D - http://www.intc.com/intelAR2011/business/research/ - while ARM isn't worth $1b. It may take a few years but Intel are seriously massive, they'll soon be the go to guys for mobile. Plus (according to rumours) with Haswell focusing on power saving, it could be a big leap forward.


    Didn't Qualcomm alone overtake AMD as a chipmaker? The thing about ARM is that anyone can get a licence for the ISA and build a custom core around it, like Krait.
    4
  • And the Chromebook with an A15. We're looking at several other SoC's but what's empowering is how simple math can help you look at efficiency.

    But it's Christmas Eve, and sometimes there are more important things than running benchmarks and soldering wires to SoCs. ;)
    14
  • Measurements taken when running Windows. Arm and Intel chips both require different coding styles to make them preform. The way windows has been coded favours the Intel Arch. Intel chips like to lean heavy on their cache, Arm chips prefer code to do as much processing on it's data as it can using all it's registers before moving on.

    Bit like comparing a 4x4 and a sports car in a muddy field.
    -5
  • nvidia tegra 3 is a piece of overhyped garbage.
    -3
  • of all the ARM types, u took one of the weakest one? I like to see the numbers vs Qualcomm krait and Apple's A6
    16
  • down with arm! if i ever do use a tablet (wont be anytime in the foreseeable future) i want to be able to run x86 programs.
    -5
  • just another article showing how much of a piece of crap tegra is.
    8
  • I agree that it will be interesting to see ARM based tablets/phones to battle with upcoming Intel Atom cpu's in tablets (and phones?). Intel's really stepping up their game and it'll just force ARM to step up theirs.

    We're already at quad-core ARM SoC's running at up to 1.7ghz. My understanding is that they won't be able to run too much faster anymore and will instead have to do more work per cycle. I think that's where Atom has the advantage in this case, which is why they can run slower but still accomplish the same amount of work with less power (but not faster).

    If only this would translate into the Desktop/Laptop sector. We haven't had huge performance gains in the longest time. I miss the old days of Athlon 64...
    3
  • Once again, Intel manages to sort of tie with a middle-of-the-pack last-generation ARM CPU, well done.

    Tegra 3 is junk and everybody knows it, bring on the Samsung Chromebook or a comparable tablet running an A15, and run Linux on them. Or rather than just waiting for Tom's to do it, check out the benchmarks on Phoronix that show the A15 eating the Atom for breakfast...
    8
  • @jessica. Phoronix tested the older Atom which we note has the same name but nowhere near the same performance or energy efficiency. Also keep in mind that Phoronix didn't actually try to run their benchmarks off the battery. A15 is fast, but the performance isn't free.

    The advertised battery life on a Chromebook is very telling. It gets 6.5 hours of web browsing with a 30 watt-hour battery, so it's drawing 4.62W under that workload. This Atom tablet is drawing closer to 3.11W under an average web browsing workload and the Tegra 3 is drawing about 3.9W. We're looking at Snapdragon next and then A15, but I think everyone's going to be surprised once they look at the actual numbers when you're running apps other than Phoronix's benchmarks.
    5
  • Alan: But the new mobile Atom is slower than the old netbook Atom, which is why you never see them in the same benchmark. Those power savings weren't free, and yet the A15 still destroys either Atom.
    2
  • Geekbench would argue differently.

    Atom Z530 (the "Z-class" Atom Phoronix tested).
    http://browser.primatelabs.com/geekbench2/search?utf8=%E2%9C%93&q=z530

    Atom D525 (the fastest netbook Atom Phoronix tested, which beats Exynos Dual in some applications)
    http://browser.primatelabs.com/geekbench2/search?utf8=%E2%9C%93&q=d525

    http://www.phoronix.com/scan.php?page=article&item=samsung_exynos5_dual&num=5

    Atom Z2760
    http://browser.primatelabs.com/geekbench2/search?utf8=%E2%9C%93&q=z2760

    The Atom D525 had a TDP of 15W in 2010. The Atom Z2760 has the same performance with a TDP of
    7
  • less than 2W. The Exynos has a TDP of 4W.

    If the A15 is 2x the power consumption, is it consistently 2x as fast?
    8
  • Jessica... you couldn't be more wrong. Good grief!
    -4