The x86 Power Myth Busted: In-Depth Clover Trail Power Analysis
by Anand Lal Shimpi on December 24, 2012 5:00 PM ESTPower During Boot
For the next test I measured power during a cold boot process. Here we're looking at power consumption from device off to hitting the Windows Start Screen:
Now we get our first glimpse of active power and there's a definite advantage here for Intel. Peak power consumption for the entire tablet tops out at just over 5W compared to 8W for Surface RT. Let's dig deeper to find what is responsible for the added power consumption:
The difference in average CPU power consumption is significant. Tegra 3 pulls around 1.29W on average compared to 0.48W for Atom. Atom also finishes the boot process quicker, which helps it get to sleep quicker and also contributes to improved power consumption.
GPU power is a big contributor as well with Tegra 3 averaging 0.80W and Atom pulling down 0.22W.
Launching Word 2013
As another simple test, I looked at power consumption while launching Microsoft Word 2013 on both platforms:
Here both tablets seemed to finish in about the same time but if you look at the power consumption graph you'll see that the W510 actually took a little bit longer. The difference wasn't great enough to really change the power profile: NVIDIA consumed 0.60W on average for its CPUs, while Intel pulled 0.48W on average:
Once again, there's a pretty stark difference on the GPU rail which makes me wonder if we're not looking at more than just GPU power here. Either that or Tegra 3's GPU implementation isn't all that power efficient compared to Imagination's. For the raw averages you're looking at 0.73W for NVIDIA compared to 0.23W for Intel.
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yyrkoon - Tuesday, December 25, 2012 - link
same OS, different HAL.Krysto - Monday, December 24, 2012 - link
Good job comparing a last-gen chip like Tegra 3 with Intel's latest Atom chip, Anand. Just because Microsoft is too slow to adopt a cutting edge ARM chip for Windows, doesn't mean Intel is now "toe to toe" with ARM.Compare Nexus 10 and iPad 4 with Clover Trail in GPU performance and price, and then let me know how it went.
croc - Monday, December 24, 2012 - link
People that tend to use terms like 'fact' also seem to be such complete tools...Barnassey - Monday, December 24, 2012 - link
My main thing is why is anand comparing a QUAD core cpu to a DUAL core With hyper-threading cpu? Of course the hyperthreading cpu will use less power.Reikon - Monday, December 24, 2012 - link
Because the dual core CPU still outperforms the quad core one?Barnassey - Monday, December 24, 2012 - link
No because the power consumption will be different. Thats the point im trying to make. Plus anand has shown hes a little biased over the years.r1cky4n - Monday, December 24, 2012 - link
a single atom core is not equivalent to a single a9 coreThe important metric is performance/watt, not watt/core
sseemaku - Tuesday, December 25, 2012 - link
So you want them to disable one of the channels in memory controller and reduce the cache size to match tegra3 for a fair comparison?tempestglen - Monday, December 24, 2012 - link
It seems that "GPU Workload" and ""Photo Enhance" CPU consumption on summary table are inconsistent with diagrams.tempestglen - Monday, December 24, 2012 - link
It also seems that Kraken test diagram of total platform power is just same as cpu only diagram. I guess anandtech posted a wrong picture.Merry Christmas!