The x86 Power Myth Busted: In-Depth Clover Trail Power Analysis
by Anand Lal Shimpi on December 24, 2012 5:00 PM ESTFinal Words
Ultimately I don't know that this data really changes what we already knew about Clover Trail: it is a more power efficient platform than NVIDIA's Tegra 3. I summed up the power consumption advantage in the table below (I left out the GPU numbers since I'm not totally clear with what NVIDIA attaches to the GPU power rail on Tegra 3):
| Power Consumption Comparison | ||||||||
| Surface RT | W510 | Surface RT (CPU) | W510 (CPU) | |||||
| Idle | 3.182W | 2.474W | 70.2mW | 36.4mW | ||||
| Cold Boot | 5.358W | 3.280W | 800mW | 216mW | ||||
| SunSpider 0.9.1 | 4.775W | 3.704W | 722mW | 520mW | ||||
| Kraken | 4.738W | 3.582W | 829mW | 564mW | ||||
| RIABench | 3.962W | 3.294W | 379mW | 261mW | ||||
| WebXPRT | 4.617W | 3.225W | 663mW | 412mW | ||||
| TouchXPRT (Photo Enhance) | 4.789W | 3.793W | 913mW | 378mW | ||||
| GPU Workload | 5.395W | 3.656W | 1432mW | 488mW | ||||
Across the board Intel manages a huge advantage over NVIDIA's Tegra 3. Again, this shouldn't be a surprise. Intel's 32nm SoC process offers a big advantage over TSMC's 40nm G used for NVIDIA's Cortex A9 cores (the rest of the SoC is built on LP, the whole chip uses TSMC's 40nm LPG), and there are also the architectural advantages that Atom offers over ARM's Cortex A9. As we've mentioned in both our Medfield and Clover Trail reviews: the x86 power myth has been busted. I think it's very telling that Intel didn't show up with an iPad for this comparison, although I will be trying to replicate this setup on my own with an iPad 4 to see if I can't make it happen without breaking too many devices. We've also just now received the first Qualcomm Krait based Windows RT tablets, which will make another interesting comparison point going forward.
Keeping in mind that this isn't Intel's best foot forward either, the coming years ahead should provide for some entertaining competition. In less than a year Intel will be shipping its first 22nm Atom in tablets, while NVIDIA will quickly toss Tegra 3 aside in favor of the Cortex A15 based 28nm Wayne (Tegra 4?) SoC in the first half of next year. Beating up on Surface RT today may be fun for Intel, but next year won't be quite as easy. The big unknown in all of this is of course what happens when Core gets below 10W. Intel already demonstrated Haswell at 8W - it wouldn't be too far fetched to assume that Intel is gunning for Swift/Cortex A15 with a Core based SoC next year.
Here's where it really gets tricky: Intel built the better SoC, but Microsoft built the better device - and that device happens to use Tegra 3. The days of Intel simply building a chip and putting it out in the world are long gone. As it first discovered with Apple, only through a close relationship with the OEM can Intel really deliver a compelling product. When left to their own devices, the OEMs don't always seem to build competitive devices. Even despite Intel's significant involvement in Acer's W510, the tablet showed up with an unusable trackpad, underperforming WiFi and stability issues. Clover Trail has the CPU performance I want from a tablet today, but I want Apple, Google or Microsoft to use it. I do have hope that the other players will wake up and get better, but for next year I feel like the tune won't be any different. Intel needs design wins among the big three to really make an impact in the tablet space.
The good news is Microsoft is already engaged with Surface Pro. It's safe to bet that there will be a Haswell version coming as well. Now Intel just needs an iPad and a Nexus win.
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snoozemode - Monday, December 24, 2012 - link
The difference this time is huge compared to competitors Intel has faced in its history. Its not just about specs anymore, no matter if its performance or performance per watt, its a lot more about economy and margins. Anyone with an ARM license can build a SoC and a lot of new players are coming to the game, especially from China. And players like Samsung who produces own SoCs for their own devices, soon LG and possibly Apple aswell means that the days of Intel dictating the terms and dominating the industry is just not going to happen this time.KitsuneKnight - Monday, December 24, 2012 - link
You mean it's much closer to Intel's early days, when it faced dozens of competing companies, instead of just a couple tiny ones.snoozemode - Tuesday, December 25, 2012 - link
Still very different because of ARMs business model which is nothing like the past with Intel, AMD, Cyrix, IBM etc. Intel definitely didn't became the giant it is because of products with good value. They are what they are because of continously raising the bar above everyone else from a performance standpoint at a time when performance was everyting and energy efficiency was close to nothing. And when they sometimes have failed to compete from a performance standpoint (ex AMD around 2000) they have resorted to some serious foul play.ay@m - Thursday, December 27, 2012 - link
well, what if Intel is now measuring the energy efficiency as the new performance benchmark?that's exactly what this article is pointing out, that Intel's Atom chip is starting to focus on energy efficiency and not focusing on the performance anymore...right?
so i think Intel understands now what it takes to enter the mobile market and what the end user will perceive as the new performance benchmark.
Kidster3001 - Friday, January 4, 2013 - link
You make Intel's point!Intel will continue to have the performance advantage. They are now going after the power part of the equation. When they are best at both (or at least significantly better at one and same at the other) what do think the result will be?
Kevin G - Tuesday, December 25, 2012 - link
The problem for Intel is that they'll design the SoC that they want to manufacture and not necessarily what the OEM wants. Intel could over spec an SoC to cover a broader market but at an increased die size and power consumption. Intel's process advantage mitigates those factors but they'll still be at a disadvantage compared to another SoC designer that'll make a product with the bare necessary functional blocks. For Intel to become a major mobile player, they'll have to start listening to OEM's and designing chips specific to them.yyrkoon - Tuesday, December 25, 2012 - link
Intel already is a major player in the mobile market. They have been far longer than anyone producing ARM based processors.Granted according to an article I read a few months back. Tablet / smart phone sales are supposedly eclipsing the sales of laptops, and desktops combined. whether true or not, I can see it being possible soon, if not already.
p3ngwin1 - Tuesday, December 25, 2012 - link
yep, it's also about PRICE.if you've seen the price of the cheap Android tablets and devices, you know Intel will have to either convince us we need to pay a premium for the extra battery-life and performance, or they're going to have to lower their prices to compete aggressively.
you can buy decent SoC's from Allwinner, Rockchip, Nvidia, Qualcomm, etc that deliver "good enough" specs and a decent price, while Intel charges a premium for it's processors.
those cheap China SoC's like Rockwell and Allwinner, etc are ridiculously cheap and you can get Android 4.1 Tablets with 1.6Ghz dual-core ARM A9 processors with Mali400 GPU's and 7" 1200x720 screens for less than $150.
Intel charges way more for their processors compared to the ARM equivalents.
name99 - Tuesday, December 25, 2012 - link
The price issue is a good point.A second point is to ask WHY Intel does better in this comparison. I'd love to see a more detailed exploration of this, but maybe the tools don't exist. However one datapoint we do know is this
(a) SMT on Atom is substantially more effective than on Nehalem/SB/IB. Whereas on the desktop processors it gets you maybe a 25% boost (on IB, worse on older models), on Atom it gets you about 50%. (This isn't surprising because Atom's in-order'ness means there are just that many more execution slots going vacant.)
(b) SMT on Atom (and IB and SB, not on Nehalem) is extremely power efficient.
So one way to run an Atom and get better energy performance than CURRENT ARM devices is to be careful about using only one core, dual threaded, for as long as you can (which is probably almost all the time --- there is very little code that makes use of four cores, or even two cores both at max speed).
I bring this up because this sort of Intel advantage is easily copied. (I'm actually surprised it hasn't already been done --- in my eyes it's a toss up whether Apple's A7 will be a 64-bit Swift or a Swift with SMT. There are valid arguments either way --- it's in Apple's interests to get to 64-bit and a clean switchover as fast as possible, but the power advantages in SMT are substantial, since you can keep your second core asleep so much more often.)
Once you accept the value of companion cores it becomes even more interesting. One could imagine (especially for an Apple with so much control over the OS and CPU) a three-way graduated SOC, with dual-core OoO high performance cores (to give a snappiness to the UI), a single in-order SMT core (for work most of the time), and a low-end in-order core (for those long periods of idle punctuated by waking up to examine the world before going back to sleep). The area costs would be low (because each core could be a quarter or less of the area of its larger sibling; the real pain would be in writing and refining the OS smarts to use such a device well. But the payoff would be immense...
Point is --- I wouldn't write off ARM yet. Intel has process advantages, and some µArch advantages. But the µArch advantages can be copied; and is the process advantage enough to offset the extra cost (in dollars) that it imposes?
Kidster3001 - Friday, January 4, 2013 - link
big.LITTLE is a waste of time. It is a stop-gap ARM manufacturers are using to try and keep the power down. As they increase performance they are not able to keep power in the envelopes they thought they could. It is far more efficient to have cores that are capable of filling all the roles you suggest by dynamically changing how they operate. This is where Intel will succeed, just look at what Haswell can do.