Power, Heat, And Efficiency
We mentioned earlier that the 1,000W power supply was probably a bad choice, since the 850W version was cheaper and had a higher efficiency rating. Let’s see how far overboard we went.
At our maximum overclock and with an unrealistically high load of three threads of Prime95 and with the fourth CPU core dedicated to FurMark's full-load graphics test, the overclocked configuration consumed a mere 879W from the wall. At our power supply’s approximate 82% efficiency (see chart), we really only needed a power supply with around 720W capacity. Thus, the super-efficient 80 PLUS Gold rated Corsair CMPSU-850HX could have been a great choice while providing enough extra power capability to support future upgrades.
Heat change from overclocking was minimized through increased fan speed.
With an average performance gain of 17% and an average power increase of 20%, the system loses 2% overall efficiency.