Power consumption is very important today, especially if you are running a room full of workstation/server systems. Adopting a series of more efficient machines could save a business thousands a year.
We used a calibrated meter to measure the power at the wall. No monitors were factored into the readings. All systems included the same graphics card, memory configuration and hard drive population.
We measured wattage at the socket when running Cinebench R11.5 64 bit which loads all cores to 100% utilisation. The graphics card was inactive during the reading.
The pair of Intel Xeon E5 2687W processors consume significant power, taking 429 watts at the socket, compared to 213 from the 3960K at reference clock speeds. That said, when the 3960K gets almost 1.5 volts @ 4.8ghz, it consumes 440 watts.
We can only imagine the power consumption of two 2687W processors if Intel would let us overclock them while increasing the voltage.