Power, Heat, And Efficiency
We set all motherboards to their default settings and enable any disabled power-saving technologies prior to benchmarking and taking power measurements. Charted values include power supply loss and off-board devices such as the 39 W liquid cooling system!
The P9X79 WS is by far the most miserly, so we also expect it to be the most efficient. Perhaps the CPU voltage regulator is part of this equation?
The draft from our liquid cooling system was enough to keep these voltage regulators at safe temperatures. We thought a fan might be needed during our overclocking tests, and the second measurements taken prior to that test emulate the cooling benefit of a downward-facing CPU cooler.
Efficiency compares work done to energy consumed. We calculated the average performance of each motherboard relative to the other motherboards in this comparison and found an average difference of less than 1%.
The term relative in our efficiency chart refers to the average of all systems. For example, the P9X79 WS consumed 96.28% of the average power of all systems and achieved 100.48% of the average performance. Dividing the second number by the first reveals a 104.4% efficiency rating.
Of course nothing is 100% efficient. Moving the baseline from 100% to 0% is as easy as subtracting one from the results, allowing the chart to show how much better or worse is each system’s efficiency compared to average. The P9X79 WS takes first place here, while the P9X79 Deluxe drops to the bottom. Asus blames the Deluxe version’s added features and voltage regulator components, and that sounds like a viable explanation to us.