We performed our power consumption measurements using an Extech Power Analyzer 380803. This device is connected before the PSU and measures the power draw of the entire system (without the monitor), including the power loss that occurs in the PSU itself. In the idle mode we start the system up and wait until it stops accessing the hard disk. Then we use LinX to load the CPU, and LinX and MSI Kombustor working simultaneously - to create complex heavy load.
Since Turbo Core technology lowers the processor frequency below the nominal value under heavy CPU load, the actual system power consumption in nominal mode is impossible to measure accurately. Therefore, we had to find a compromise and disable the CPB Mode parameter in the mainboard BIOS. This is a pretty serious allowance, which changes the system behavior dramatically, but nevertheless we believe that the obtained results are credible enough. The thing is that LinX utility loads the CPU extremely heavily, much more than you would anticipate from regular programs. As a result, despite the fact that CPB Mode parameter has been disabled, the measured system power consumption under heavy load created by LinX turns out about the same as we observed in real applications launched with enabled Turbo Core technology. We applied the same principle when we selected utilities for creating complex system workload. When we chose programs responsible for heavily loading individual system components, we made sure that they created about the same need for power as real application would in every-day usage scenarios. The results on the following diagrams are arranged in an ascending order for power consumption.
We criticized the ASUS F2A85-V PRO for its indecently high power draw in comparison with the Gigabyte mainboard, but the ASRock FM2A85X Extreme6 outdid Asus in this respect. The Digi Power voltage regulator with 8+2 power phases is touted by ASRock as one of the key advantages of this mainboard, but it seems to be an overkill for a Socket FM2 processor as is indirectly confirmed by the power consumption results in the overclocked mode.
The power consumption of the ASRock mainboard is still very high in idle mode and at low loads, but not higher than that of the ASUS board. At high loads ASRock board needs less power than the ASUS board, getting closer to the level of the energy-efficient mainboard from Gigabyte. Thus, the advanced power system of the ASRock mainboard is efficient at high loads only, yet the Gigabyte always consumes less. We guess ASRock’s voltage regulator doesn’t do well in nominal mode or is not balanced enough. It is not surprising that the heatsink mounted on its components was so hot all the time.
We can also compare the mainboards in terms of their standby power draw. Our tool can report this parameter but we didn’t publish such data in our earlier tests. The amount of power consumed in such mode is usually 1.5 or 2 watts, which is not much, but the ASRock FM2A85X Extreme6 consumes about 5 watts as soon as you connect power to it. The number is still not very high and we've never taken much notice of this parameter with other mainboards, yet it seems to be higher than usual. ASRock was among the first mainboard makers to implement ErP/EuP standards that define power consumption limits in standby mode, but the BIOS of the ASRock FM2A85X Extreme6 doesn’t even offer an option to enable that technology.