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
Cortex A15: SunSpider 0.9.1
SunSpider performance in Chrome on the Nexus 10 isn't all that great to begin with, so the Exynos 5250 curve is longer than the competition. I wouldn't pay too much attention to overall performanceas that's more of a Chrome optimization issue, but we begin to shine some light on Cortex A15's power consumption:
Although these line graphs are neat to look at, it's tough to quantify exactly what's going on here. Following every graph from here on forward I'll present a bar chart that integrates over the benchmark time period (excluding idle) and presents total energy used during the task in Joules.
The data here reflects what you see in the chart above fairly well. Acer/Intel manage to get the edge over Dell/Qualcomm when it comes to total energy consumed during the test. The Nexus 10 doesn't do so well here but that's likely a software issue more than anything else.
CPU power is just insane. Peak power consumption is around 3W, compared to around 1W for the competition.
Looking at the CPU core itself, Qualcomm appears to have the advantage here but keep in mind that we aren't yet tracking L2 cache power on Krait (but we are on Atom). Regardless Atom and Krait are very close.
Even GPU power consumption is pretty high compared to everything else (minus Tegra 3).
SunSpider - Max, Avg, Min Power
For your reference, the remaining graphs present max, average and min power draw throughout the course of the benchmark (excluding beginning/end idle times).
Average Power Draw
Minimum Power Draw
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kumar0us - Friday, January 4, 2013 - link
My point was that for a CPU benchmark say Sunspider, the code generated by x86 compilers would be better than ARM compilers.Could better compilers available for x86 platform be a (partial) reason for faster performance of intel. Or compilers for ARM platform are mature and fast enough that this angle could be discarded?
iwod - Friday, January 4, 2013 - link
Yes, not just compiler but general optimization in software on x86. Which is giving some advantage on Intel's side. However with the recent surge of ARM platform and software running on it my ( wild ) guess is that this is less then 5% in the best case scenario. And it is only the worst case, or individual cases like SunSpider not running fully well.jwcalla - Friday, January 4, 2013 - link
Yes. And it was a breath of fresh air to see Anand mention that in the article.Look at, e.g., the difference in SunSpider benchmarks between the iPad and Nexus 10. Completely different compilers and completely different software. As the SunSpider website indicates, the benchmark is designed to compare browsers on the same system, not across different systems.
monstercameron - Friday, January 4, 2013 - link
it would be interesting to throw an amd system into the benchmarking, maybe the current z-01 or the upcoming z-60...silverblue - Friday, January 4, 2013 - link
AMD has thrown a hefty GPU on die, which, coupled with the 40nm process, isn't going to help with power consumption whatsoever. The FCH is also separate as opposed to being on-die, and AMD tablets seem to be thicker than the competition.AMD really needs Jaguar and its derivatives and now. A dual core model with a simple 40-shader GPU might be a competitive part, though I'm always hearing about the top-end models which really aren't aimed at this market. Perhaps AMD will use some common sense and go for small, volume parts over the larger, higher performance offerings, and actually get themselves into this market.
BenSkywalker - Friday, January 4, 2013 - link
There is an AMD design in their, Qualcomm's part.A D R E N O
R A D E O N
Not a coincidence, Qualcomm bought AMD's ultra portable division off from them for $65 million a few years back.
Anand- If this is supposed to be a CPU comparison, why go overboard with the terrible browser benchmarks? Based on numbers you have provided, Tegra 3 as a generic example is 100% faster under Android then WinRT depending on the bench you are running. If this was an article about how the OSs handle power tasks I would say that is reasonable, but given that you are presenting this as a processor architecture article I would think that you would want to use the OS that works best with each platform.
powerarmour - Friday, January 4, 2013 - link
Agreed, those browser benchmarks seem a pretty poor way to test general CPU performance, in fact browser benchmarks in general just test how optimized a particular browser is on a particular OS mainly.In fact I can beat most of those results with a lowly dual-A9 Galaxy Nexus smartphone running Android 4.2.1!
Pino - Friday, January 4, 2013 - link
I remember AMD having a dual core APU (Ontario) with a 9W TDP, on a 40nm process, back in 2010.They should invest on a SOC
kyuu - Friday, January 4, 2013 - link
That's what Temash is going to be. They just need to get it on the market and into products sooner rather than later.jemima puddle-duck - Friday, January 4, 2013 - link
Impressive though all this engineering is, in the real world what is the unique selling point for this? Normal people (not solipsistic geeks) don't care what's inside their phone, and the promise of their new phone being slighty faster than another phone is irrelevant. And for manufacturers, why ditch decades of ARM knowledge to lock yourself into one supplier. The only differentiator is cost, and I don't see Intel undercutting ARM any time soon.The only metric that matters is whether normal human beings get any value from it. This just seems like (indirect) marketing by Intel for a chip that has no raison d'etre. I'm hearing lots of "What" here, but no "Why". This is the analysis I'm interested in.
All that said, great article :)