For all testing on the $700 PC, power-saving features were disabled and Windows 7’s power options were set to high performance. Let’s take a look at the total system-power usage measured from the AC source.
We normally see excellent power-consumption numbers for a dual-core Wolfdale processor, but the pair of Radeon HD 4870 graphics cards drastically impacts both idle and load consumption. Peak usage of less than 500W at the AC source should erase any doubts about whether the EarthWatts EA650 was enough power supply for the system.
Although the system was stable without taking these measures when overclocking, we did turn both the Antec Two-Cool exhaust fans up to high and increased the graphics card fans to 85%. As a result, GPU temperatures were lower on our overclocked system than at stock speeds with auto-fan settings. Heat was definitely not an issue and with cool winter ambient temperatures, we likely could have run the Pentium E5300 at 3.9 to 4.0 GHz if we had been willing to push the required voltage.