In the past I've posted several articles on various tweaks to improve Power Management on Intel Sandy/Ivybridge hardware, based on my experiments with my Lenovo X220

With more recent releases of openSUSE, I've been experimenting with my old tweaks, and found that they NO LONGER help with power management - In fact, they seem to increase it

So, my advice at the moment - if you want a Linux OS that has good Power Management on a Lenovo X220 or similar laptop.. install openSUSE Tumbleweed, and don't change the default settings :)