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. For a more illustrative picture there are graphs that show how the computer power consumption grows up depending on the number of active execution threads in LinX (both at the default and overclocked system settings).
Throughout this review we mentioned that not all power-saving technologies were enabled by default. Sicne the boards are very similar and not only perform equally fast, but also consume equal amount of power, we decided to slightly change our testing approach for one of them. During our tests on the Intel DZ77RE-75K we didn’t change any of the settings, while Intel DZ77GA-70K was tested with all power-saving technologies enabled manually. The difference turned out quite significant especially in idle mode. Both these boards could easily fall in the leading group, but their power consumption values exceed the average level when they are tested with default settings. The difference is even noticeable in case of single-threaded load, although it grows smaller as the load increases and disappears completely under maximum load.
We enabled all power-saving technologies during overclocking. Besides, Intel mainboards didn’t overclock the processor to its maximum. Therefore, both tested mainboards look very attractive in terms of energy-efficiency, although they still yield to MSI Z77A-GD65. The gaming Gigabyte board supports advanced functionality with multiple graphics cards due to integrated additional PCI Express bus hub, but higher power consumption is the price it has to pay in this case.