ARM Vs. x86: The Secret Behind Intel Atom's Efficiency
Intel recently shared very granular power measurements of its Atom SoC and Nvidia's Tegra 3. If you previously believed ARM's architecture to be inherently more efficient, perhaps you underestimated the benefit of Intel's manufacturing and architecture.
Windows 8 Gestures: Latency And Power Consumption
| Microsoft Surface | ||||||||
|---|---|---|---|---|---|---|---|---|
| Row 0 - Cell 0 | 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) | 133.3 | 38 | 6.06 | 1.07 | 0.97 | 0.77 | 0.98 | 2.27 |
| Bing Maps (Split-Screen / Drag) | 125 | 45.6 | 5.80 | 0.80 | 0.76 | 0.96 | 0.98 | 2.30 |
| Bing Maps (Split-Screen / Flick) | 175 | 57.6 | 5.65 | 0.98 | 0.92 | 0.60 | 0.99 | 2.16 |
| Wikipedia (Split-Screen / Pinch) | 158.3 | 55.3 | 5.28 | 0.97 | 0.75 | 0.47 | 0.99 | 2.10 |
| Wikipedia (Split-Screen / Drag) | 183.3 | 57.2 | 4.92 | 0.70 | 0.72 | 0.46 | 0.98 | 2.06 |
| Wikipedia (Split-Screen / Flick) | 183.3 | 60 | 4.89 | 0.66 | 0.70 | 0.49 | 0.99 | 2.07 |
| Acer W510 | ||||||||
|---|---|---|---|---|---|---|---|---|
| Row 0 - Cell 0 | 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) | 83.3 | 33.8 | 5.50 | 0.76 | 0.50 | 0.54 | 1.24 | 2.47 |
| Bing Maps (Split-Screen / Drag) | 91.7 | 42.4 | 5.36 | 0.72 | 0.55 | 0.55 | 1.25 | 2.28 |
| Bing Maps (Split-Screen / Flick) | 116.7 | 56.2 | 4.96 | 0.58 | 0.45 | 0.49 | 1.23 | 2.22 |
| Wikipedia (Split-Screen / Pinch) | 75.0 | 53.7 | 5.07 | 0.82 | 0.34 | 0.44 | 1.28 | 2.19 |
| Wikipedia (Split-Screen / Drag) | 150 | 59.2 | 4.76 | 0.64 | 0.31 | 0.44 | 1.26 | 2.10 |
| Wikipedia (Split-Screen / Flick) | 83.3 | 56.5 | 4.53 | 0.59 | 0.32 | 0.42 | 1.26 | 1.94 |
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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Novuake Excellent! Was wondering about this for some time. Also made the mistake of thinking Intel was behind in the mobile space... Well done Toms.Reply -
tipoo 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.Reply
I'm thinking in the coming years, Intel vs ARM will become a more interesting battle than Intel vs AMD. -
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.Reply -
blubbey tipoo I'm thinking in the coming years, Intel vs ARM will become a more interesting battle than Intel vs AMD.Reply
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. -
tipoo 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.Reply
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. -
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.Reply
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tipoo 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.Reply
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.
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AlanDang 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.Reply
But it's Christmas Eve, and sometimes there are more important things than running benchmarks and soldering wires to SoCs. ;) -
richarduk 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.Reply
Bit like comparing a 4x4 and a sports car in a muddy field.