There's Another Linux Kernel Power Problem
When running graphics tests on the different kernels, the 3.6 and 3.7 kernels aren't at a sizable premium in terms of power consumption. But with the Linux 3.6 kernel there weren't any major Intel DRM driver changes like changing RC6 or other power-savings features to explain if this regression is concerning Intel graphics.
The raw performance in these graphics tests is also unchanged when moving from Linux 3.5 to 3.6 and beyond.
C-Ray is another computational test where it shows on average that the Linux 3.6 and 3.7 kernels are burning through about 20% more power than the earlier kernels.