Power consumption
As a reminder, all systems have the GeForce GTX 780 in situ. Idle power consumption, evaluated as the system 'sitting' on the Windows Desktop screen, is commendable for high-performance machines.
2D power is defined as the maximum at-mains power reported when running the all-core wPrime stress-test. The fewer cores/threads of Haswell means it does a lot better than the competition, but the Ivy Bridge-powered Core i7-4960X isn't the voracious energy beast that you may at first believe it to be.
3D power, on the other hand, is the highest seen when running the DiRT Showdown benchmark. This benchmark is a mixture of CPU and GPU load, and the relatively minor differences between platforms indicates that the GPU's energy requirement is largely masking CPU-side advantages. Core i7-4960X remains a decent performer, especially with due knowledge of its 6C/12T architecture.
We run these tests with fully-built systems. This is an important fact to consider when thinking about PSUs, because even a Core i7-4960X and enthusiast-class GTX 780 barely tickle the capacity of the Corsair AX760i PSU.