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. Because of compatibility issues we uncovered in Gigabyte GA-Z77X-UP4 TH and Gigabyte GA-Z77X-UP5 TH mainboards with our original CoolerMaster RealPower M850 power supply unit, we had to replace it with Enermax NAXN ENM850EW. Both these PSUs have very similar technical characteristics, but Enermax NAXN ENM850EWT is about 1-3 W more energy-efficient than the Cooler Master unit. In order to be able to use the previously obtained results, we decided to make up for this efficiency difference by adding 2 W to all new power readings, so that we could still compare their results against the power consumption of all previously tested products.
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). The results of ASRock Z77 Extreme3 are marked with darker color for your convenience.
As we can see, ASRock Z77 Extreme3 is pretty energy-efficient in all modes when working at nominal settings. However, we have already mentioned that there is a way to slightly lower the idle power consumption even more by manually enabling all power-saving settings or by using the proprietary “Power Saving Mode” parameter.
During overclocking the mainboard’s idle power consumption is a little below average, its power consumption under small operational loads is pretty low, and only reaches the average level under maximum loads. I have to remind you that this mainboard managed to overclock our processor to the maximum frequency of 4.6 GHz, unlike many other mainboards reviewed before, so the slightly higher power consumption under heavy load is quite normal.