This is really interesting. I wonder how the Apple A6 would do since it's after all the most powerfull ARM soc today. But I guess that would be difficult to test unless PTS is ported to iOS.
If I remember correctly the Exynos 5 has a TDP of 4 W compared to the Atom D525's 13 Watt, and yet the Exynos 5 is mostly faster. And again, it's not even the fastest ARM soc available. This is after Intel has spent several years developing the atom. I can't help to think that perhaps the x86 is too complex to ever be really power efficient.