After running each of those tests of a clean install of Fedora 23, Fedora 23 with all available stable release updates as of this past weekend (thus at Linux 4.4), and then enabling the Rawhide Nodebug repository for access to Linux 4.6 Git, I ran power consumption tests for the ThinkPad X1 Carbon with i7-5600U CPU while this notebook/ultrabook was running on battery power.
I was interested due to my recent results of Linux 4.5 Appears To Slightly Lower Power Use, But Linux 4.6 Will Be Even Better when testing on a Core i7 Haswell ASUS ultrabook.
While idling, there was barely any difference with the power consumption under these different Fedora 23 configurations...So it's either due to the F23 kernel configuration or with this particular ThinkPad X1 Carbon model there is little benefit from the latest kernels. Then again, this Broadwell unit is much more efficient than the Haswell laptop tested in the previous article.
The results under load there is minimal difference, but perhaps worthy of being pointed out is that the minimum power use was lower under the updated Fedora 23 stack. You can dig through these power use numbers under load via this OpenBenchmarking.org result file.
When I find the time and if there's enough reader interest, happy to run some more power consumption tests of recent kernel releases / distributions on the few other relatively modern ultrabooks/laptops in my possession.