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.
Throughout this review we most often saw Asus mainboard slightly ahead of the competition, but things changed to their complete opposite during the power consumption tests: this is where Gigabyte mainboard consumes less power. Unlike the performance tests, the difference here is obvious and sometimes even extremely significant. However, Asus F2A85-V PRO mainboard does have a few reserves left: you can disable the EPU Power Saving Mode parameter in the mainboard BIOS. You may adjust the savings range to your liking, depending on the specific system functionality and usage model. As for us, we decided to leave it at Auto. In this case the power consumption of systems based on different mainboards becomes comparable. The next diagram shows the difference between the nominal and power-saving mode on the same Asus mainboard.
However, once we get to overclocking, Gigabyte mainboard again takes the lead away from Asus: it consumes less power in any operational mode and under any type of load. The systems power consumption will be very similar only in very compute-intense applications. In all other cases Asus mainboard will be consuming more energy, while its performance will be practically the same.