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.
Facebook
Twitter
RSS
140 Comments
View All Comments
karasaj - Friday, January 4, 2013 - link
Yeah, keep in mind that Haswell will be like Windows 8 Pro, i.e. a more traditional laptop experience anyways, so it won't necessarily be strictly competing with the iPad.mrdude - Friday, January 4, 2013 - link
Win8 and its devices aren't selling, so I'm not sure how Intel plans on suddenly making that OS and the products that run on it any better. Like I said, Win8 tablet sales have been really really poor.And as far as consumers go, it is directly competing with the iPad and Android. People are more inclined to buy a new shiny tablet than a laptop and they could care less for x86 compatibility. For your average user, the iOS app store has thousands of more applications than your x86 desktop if only for the fact that it makes it incredibly easy to search through, install and play with. x86 compatibility means very little to most folks, and you can argue that it's actually a detriment due to the x86 legacy's inherent safety issues (non-Metro) and higher prices.
The "It's also a PC" shtick only works if people want PCs. Judging by the sales figures and the longer upgrade cycles, Win8's sales figures, it's clear they're obviously aren't that interested.
Krysto - Friday, January 4, 2013 - link
"One reason the Pro version of the device will be more expensive is that it uses a PC-style chip from Intel Corp. INTC -0.87% (INTC), part of a family of chips that sells for between $177 and $225. The Nvidia Corp. NVDA +3.48% (NVDA) chip typically used in the Surface RT model costs about $28, according to an estimate by research firm UBM TechInsights."http://blogs.wsj.com/digits/2013/01/04/windows-8-f...
iPhone 5's BOM is $188. iPad 3's BOM was $160. I wish Intel good luck if they think they are going to have competitive devices on the market where the chip alone costs as much as all the components in iPads and iPhones.
Oh, but that's just for IVB chips. Did I mention Haswell will be 40% more expensive - so Haswell chips will be more like $250-$300. Yeah...good luck with that Intel.
jeffkro - Saturday, January 5, 2013 - link
"I'm more than willing to pay for the performance premium."I'm not, I'm perfectly happy with the speed of my galaxy nexus which is completely outclassed by the Krait S4. So why would I want to pay a huge premium for an intel powered phone? Just give me dual core krait performance in a all day battery life phone and I'll be thrilled. For me getting more battery life takes precedence over all out speed.
djgandy - Friday, January 4, 2013 - link
True, pricing is another issue, but Intel has room to cut prices a lot. Intel makes the conscious decision to make upwards $30 on a chip rather than $3. In turn they don't have to ship as many chips.I'm pretty sure the cost of manufacturing an Atom SOC is around $5-6, so Intel has plenty of room to make money in the $20 if they so choose. There is no technical reason a Tegra 3 is cheaper than a Haswell when it comes to manufacturing. It's all about market segment.
Intel idling fabs a bit is probably due to the fact they went massive with 22nm. Intel also makes in profit a quarter 75% of what Nvidias entire yearly revenue is.
If Intel wants to play ball, I am sure they will.
mrdude - Friday, January 4, 2013 - link
But can they afford to?Those billion dollar fabs require billions of dollars to run, and if they want to maintain - or even stretch - their fab lead over their competitors, they need to make MORE money going forward. This means that if they were to compete at ARM level they can't afford to do so over a longer period of time else they'd find themselves short of cash to funnel back into the fabs and losing that distinct advantage. I remember seeing something that stood out in the latest Qualcomm earnings report, it read (paraphrasing): our fabless strategy is actually an advantage.
For Intel's fab advantage to remain an advantage they must make more and more money going forward. As soon as the sales figures look gloomy then it all goes downhill quickly, as the fabs go from being a distinct advantage to a potentially expensive disadvantage.
Intel also has investors to answer to, and this is more complicated than the microarchitecture involved. The investors expect >60% gross margins, and Intel dropped margins a bit below 60% but also let fabs idle so they wouldn't have to drop them even further. The mere fact they're latting fabs are idle means that they're not meeting sales estimates. That's not good. This is rather obvious and seen by the drop in chip sales over the same period last year. In order to keep that dip from looking worse (dropping margins even further), Intel just let the fabs idle. Smart short term strategy as investors don't look at that stuff, but it shows that things aren't 'all gravy.'
If Intel were to drop prices during a resurgent and strong PC market then I'd completely agree with you. They'd even be able to lose money in the SoC mobile arena and still show good numbers at their earnings call. That's just not the case, with PC sales slowing quite a bit and tablet sales picking up substantially, you'd have to question whether they can "weather the storm" by leaning on their dominant x86 PC/server position long enough to make up for the lower-than-usual prices in the mobile SoC space. If Intel went at ARM head on with competitive prices a couple of years ago there would be no question that Intel would remain competitive, but with weak PC sales that are expected to look even weaker compared to mobile this year?
If Intel is to compete with ARM on price, it's, oddly enough, going to be determined by how well their high profit products sell in the near future.
Ananke - Friday, January 4, 2013 - link
They can't compete on pricing with x86 vs ARM. I'm in the business, I know. Intel has absolutely competitive process facilities. If they were strictly making chips, nobody can beat them. If they license the design and make chips - nobody can beat them either. However, coupling the own design R&D expenses with own production, and their cost is higher. Products might be better, but cost is higher.On the marketing side, only price matters today. You may think performance is important, but in reality it defines 1% of the decision of 1% of the market....
Hence, the trend towards ARM designs. That trend was not accidental, it is structural, and I see no reason it will turn around.
It is the reason why AMD is performing so poorly, just Intel is much larger and owns its fabs, it takes longer to become obvious they will have revenue problems.
GillyBillyDilly - Saturday, January 5, 2013 - link
Exactly. Performance is one thing, Price another. ARM is not AMD. There is no way intel can compete with ARM price-wise. And the less competetative they are, the less they will sell and the less they sell, the less R&D and the less R&D, well, this goes on and on. I am glad I don't own any Intel shares.felixyang - Friday, January 4, 2013 - link
There is no doubt A15 is more power consuming. A A7 core can save power sometimes, but when you have a CPU intensive workload like sunspider, the A7 core's effect is limited.GillyBillyDilly - Saturday, January 5, 2013 - link
I hope you do realise that this website is a business and not a charity organisation, and no money = no business.Of course Anand is being paid for their reviews ( not only Intel related ) but as long as they don*t maipulate the data (which I don*t think they do ), their reviews are worth reading. You read it, get a general picture and make YOUR own conclusions.