The ARM vs x86 Wars Have Begun: In-Depth Power Analysis of Atom, Krait & Cortex A15
by Anand Lal Shimpi on January 4, 2013 7:32 AM EST- Posted in
- Tablets
- Intel
- Samsung
- Arm
- Cortex A15
- Smartphones
- Mobile
- SoCs
Final Words
Whereas I didn't really have anything new to conclude in the original article (Atom Z2760 is faster and more power efficient than Tegra 3), there's a lot to talk about here. We already know that Atom is faster than Krait, but from a power standpoint the two SoCs are extremely competitive. At the platform level Intel (at least in the Acer W510) generally leads in power efficiency. Note that this advantage could just as easily be due to display and other power advantages in the W510 itself and not necessarily indicative of an SoC advantage.
Looking at the CPU cores themselves, Qualcomm takes the lead. It's unclear how things would change if we could include L2 cache power consumption for Qualcomm as we do for Intel (see page 2 for an explanation). I suspect that Qualcomm does maintain the power advantage here though, even with the L2 cache included.
On the GPU side, Intel/Imagination win there although the roles reverse as Adreno 225 holds a performance advantage. For modern UI performance, the PowerVR SGX 545 is good enough but Adreno 225 is clearly the faster 3D GPU. Intel has underspecced its ultra mobile GPUs for a while, so a lot of the power advantage is due to the lower performing GPU. In 2D/modern UI tests however, the performance advantage isn't realized and thus the power advantage is still valid.
Qualcomm is able to generally push to lower idle power levels, indicating that even Intel's 32nm SoC process is getting a little long in the tooth. TSMC's 28nm LP and Samsung's 32nm LP processes both help silicon built in those fabs drive down to insanely low idle power levels. That being said, it is still surprising to me that a 5-year-old Atom architecture paired with a low power version of a 3-year-old process technology can be this competitive. In the next 9 - 12 months we'll finally get an updated, out-of-order Atom core built on a brand new 22nm low power/SoC process from Intel. This is one area where we should see real improvement. Intel's chances to do well in this space are good if it can manage to execute well and get its parts into designs people care about.
Device level power consumption, from our iPhone 5 review, look familiar?
If the previous article was about busting the x86 power myth, one key takeaway here is that Intel's low power SoC designs are headed in the right direction. Atom's power curve looks a lot like Qualcomm's, and I suspect a lot like Apple's. There are performance/power tradeoffs that all three make, but they're all being designed the way they should.
The Cortex A15 data is honestly the most intriguing. I'm not sure how the first A15 based smartphone SoCs will compare to Exynos 5 Dual in terms of power consumption, but at least based on the data here it looks like Cortex A15 is really in a league of its own when it comes to power consumption. Depending on the task that may not be an issue, but you still need a chassis that's capable of dissipating 1 - 4x the power of a present day smartphone SoC made by Qualcomm or Intel. Obviously for tablets the Cortex A15 can work just fine, but I am curious to see what will happen in a smartphone form factor. With lower voltage/clocks and a well architected turbo mode it may be possible to deliver reasonable battery life, but simply tossing the Exynos 5 Dual from the Nexus 10 into a smartphone isn't going to work well. It's very obvious to me why ARM proposed big.LITTLE with Cortex A15 and why Apple designed Swift.
I'd always heard about Haswell as the solution to the ARM problem, particularly in reference to the Cortex A15. The data here, particularly on the previous page, helped me understand exactly what that meant. Under a CPU or GPU heavy workload, the Exynos 5 Dual will draw around 4W. Peak TDP however is closer to 8W. If you remember back to IDF, Intel specifically called out 8W as a potential design target for Haswell. In reality, I expect that we'll see Haswell parts even lower power than that. While it may still be a stretch to bring Haswell down to 4W, it's very clear to me that Intel sees this as a possiblity in the near term. Perhaps not at 22nm, but definitely at 14nm. We already know Core can hit below 8W at 22nm, if it can get down to around 4W then that opens up a whole new class of form factors to a traditionally high-end architecture.
Ultimately I feel like that's how all of this is going to play out. Intel's Core architectures will likely service the 4W and above space, while Atom will take care of everything else below it. The really crazy part is that it's not too absurd to think about being able to get a Core based SoC into a large smartphone as early as 14nm, and definitely by 10nm (~2017) should the need arise. We've often talked about smartphones being used as mainstream computing devices in the future, but this is how we're going to get there. By the time Intel moves to 10nm ultramobile SoCs, you'll be able to get somewhere around Sandy/Ivy Bridge class performance in a phone.
At the end of the day, I'd say that Intel's chances for long term success in the tablet space are pretty good - at least architecturally. Intel still needs a Nexus, iPad or other similarly important design win, but it should have the right technology to get there by 2014. It's up to Paul or his replacement to ensure that everything works on the business side.
As far as smartphones go, the problem is a lot more complicated. Intel needs a good high-end baseband strategy which, as of late, the Infineon acquisition hasn't been able to produce. I've heard promising things in this regard but the baseband side of Intel remains embarassingly quiet. This is an area where Qualcomm is really the undisputed leader, Intel has a lot of work ahead of it here. As for the rest of the smartphone SoC, Intel is on the right track. Its existing architecture remains performance and power competitive with the best Qualcomm has to offer today. Both Intel and Qualcomm have architecture updates planned in the not too distant future (with Qualcomm out of the gate first), so this will be one interesting battle to watch. If ARM is the new AMD, then Krait is the new Athlon 64. The difference is, this time, Intel isn't shipping a Pentium 4.
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tahyk - Friday, January 4, 2013 - link
I've read that review. That's a total scam. They comparing the Atom N270, aka the original 2008 Netbook chip to the latest and greatest ARM. This article is about the Atom Z2760, so it compares 2012 x86 to 2012 ARM - a whole lot more fair.mugiebahar - Friday, January 4, 2013 - link
While I always enjoy reading here, I have to admit this article is not 1 of them. I'm not slinging mud or anything but rather I think it's highly subjective to consider @ this point intel is in good standing to make in roads. I agree intel has the technology/money/resources/will power to make a killer chip that sips power better then anyone. But as so many have pointed out and cannot be changed, Intel doesn't have the ability to do it for a cheap competitive price. ARM has always will always be better in that. It's all about how a company is built. ARM doesn't need to finance a foundry much less several like intel. With over head and size comes problems changing business models, especially in manufacturing. The thing is while we don't know yet what the future holds as to the amount of things we will do on a phone, I can guarantee I won't be ripping a DVD, making CAD drawings on it. So fundamentally we will hit a wall that the cost is not worth the money. Am I wrong? While I know what the article is pointing to, which is a strong class leading, watt sipping intel. But they cannot win or be as noteworthy as the article points out. You can't ask a company to devalue their products, Why? Because you lose either because 1) you look desperate or 2) you acknowledge that you where ripping people off before. While they may have had legitimate reasons for pricing, or that technology brought prices down its perception that's the killer. Is Atom bad? No. But ask regular joe, he'll tell you it's crap but why? Price and perception. Intel did something's right and sme wrong. They should have realized a while back desktops were good enough and push mobile chips to the better lower cost production. But now a company so heavy on top can switch just like that. Now ether they will have to restructure to be competitive in the mobile arena or just play second fiddle. But they can't right now (unless they change) be a mobile king as they are on the desk top only because of company structure nothing else.jemima puddle-duck - Friday, January 4, 2013 - link
I'd echo this sentiment. I'm getting less and less interested that so-and-so has made something slightly better than so-and-so. The chances are this Atom will never see the inside of more than 1 or 2 phones. I want to know why! This is the insight Anandtech, with its extensive contacts, can deliver! I guess what I'm asking for is more politics and less technology :-)vngannxx - Friday, January 4, 2013 - link
Anandtech should rerun the nexus 10 benchmark with the aosp browser.mugiebahar - Friday, January 4, 2013 - link
While Intel is the 800lb Gorilla that there is no doubt. Problem is its not stuck in a room with a monkey and a chimpanzee (AMD and VIA) this time it's in a room with a Lion (Apple) Tiger (say Samsung) Siberian Tiger (Qualcomm) mountain lion (TI) baby cub (AMD) and a litter full of Chinese cats. So the Gorilla is the strongest but now he might just have the hair bit of his ass cheeks if he doesn't watch it. Please feel free to reorder the cats to a better resemblance to whoever as I just thought about it quickly, but I think you can agree True?UpSpin - Friday, January 4, 2013 - link
Intel PR, nothing more.This article is misleading, confusing and compares totally different things. It's a shame to see such a bad written article on Anandtech, full with meaningless, misleading, graphs, which just sit there, without any further descriptive text. If a image isn't worth some text, it isn't worth to get shown at all!
1. There's no use in showing and even comparing Total Power Consumption numbers, because the systems are totally different. So don't show them! Everything else is misleading, most probably on purpose because the absolutely low-end Intel device looks good in this comparison, logically. But please, if you can't compare things, don't try to compare them. And if you can't compare them, also don't further use such numbers, like in Task Energy Total Platform. It's useless.
You can't measure Qualcomm chips correctly, thus include Total Platform power draw? Poor excuse. If you can't measure it, don't post it, but don't post false and misleading numbers.
2. What is Average Power Draw? What's the use of it? You don't use those graphs in your Article at all! Do you know what this means? Exactly: Those graphs are useless and meaningless. Why do you post them? They are redundant because of the Energy graphs. So naturally, because of the much shorter run time of the A15 SoC, the Average graph looks disadvantageous for ARM, which is simply misleading. But well Intel is probably happy you posted hit and thanked you with cash, why else should a sane person post such misleading stuff.
3. GPU Power: What game? How did it run? Off-Screen? The same resolution on every tablet? The same API? The same FPS? It's not surprising that a low-end GPU struggling to keep maybe 10FPS consumes less power than a high-end GPU displaying 60FPS at a higher resolution. You haven't said anything about this issue, yet happily compare meaningless numbers.
I'm sorry but this article is, right now, garbage. And the only reason for posting such a poor written article is that Intel must have paid you a lot of money for doing so.
It's nice that you post such semi-scientifical articles, but the way you do in this case isn't great.
This article is very very hard to read, because the reader has to do ALL the interpretation.
You could remove 2/3 of all graphs, and the article would contain the same information.
By just looking at the graphs Intel is the overall winner, which is, if you do some further comparisons based on your article wrong. At most Intel is, according to your graphs, on par with A15, CPU wise, which still is a nice outcome for Intel.
The GPU is awful in the Intel SoC, the CPU competive.
The A15 GPU is perfect, the CPU at least as efficient as the Intel one, but much faster.
Yet, because the article is so confusing and I don't want to waste any further time doing the work a good writer should have done, I see ARM as the clear winner.
Same or more efficient CPU, much faster CPU, much better GPU, overall winner!
Similar argumentation for Tegra and Krait.
Intel has a good CPU, but the SoC looks awful.
powerarmour - Friday, January 4, 2013 - link
"I see ARM as the clear winner.Same or more efficient CPU, much faster CPU, much better GPU, overall winner!
Similar argumentation for Tegra and Krait.
Intel has a good CPU, but the SoC looks awful."
That was exactly my conclusion reading through it, I just couldn't be bothered to be eloquent enough to explain it like that as it seemed obvious to me.
I look at the SoC as a whole, and apart from a 'slight' advantage on the CPU side in a few select (and likely x86 optimized) browser benchmarks, the Clover Trail SoC is really quite lacklustre.
mfergus - Friday, January 4, 2013 - link
The GPU in the clover trail soc isn't even made by Intel. They could swap it out for anything they wanted tho they want it to be an in house gpu.Cold Fussion - Saturday, January 5, 2013 - link
I concur, the article is pretty bad as it stands. Apart from all the poorly presented information, it should have had tests done on an andriod tablet running the same krait SOC as the windows tablet so we establish how the different operating systems affect power draw. Without that I don't see how they can reasonably establishes the differences between A15 and the others.wsw1982 - Friday, January 11, 2013 - link
http://www.phonearena.com/news/Intel-Atom-powered-...check this out... The clove trail+ in smart phone lenovo K900 scores more than 25000 in Antutu on a 1080P display, which just crush snapdragon pro (4 krait) in Optimus G, and the beloved Samsung Exynos 5440 (2 A15) in Nexus 10...
So, what gonna be the next far cry from ARMy: "Intel cannot make low power chips"? Oh, no, that's already busted. Then, I guess it gonna be "Intel cannot sell smartphone chips as cheap as others" or "We don't care performance and we don't care battery life, we just care the compatibility to IOS"