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). The results of Asus Maximus V Formula are marked with darker color for your convenience.
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.
In nominal mode, the power consumption of Asus Maximus V Formula under load is a little above average, which is quite typical of the flagship Asus mainboards. However, we were quite concerned with the board’s extremely high power consumption in idle mode. Asus Maximus V Formula only beat two other products, which owe their high power consumption in idle mode to the use of the PLX PEX 8747 hub. The diagram below will explain where the problem is. When all power-saving technologies are enabled, the power consumption of Asus Maximus V Formula mainboard has barely changed, but in idle mode it dropped by as much as 10 watts! It seems that when the power-saving parameters are set to “Auto”, they simply do not work and therefore they must be manually enabled.
We use only energy-efficient overclocking methods, which will allow using the system in this mode for an extended period of time with all power-saving technologies up and running as they should. Therefore, when the overclocked system is idling or under low operational load, the power consumption of Asus Maximus V Formula stays at the company’s typical level – a little above average. Under maximum load it even drops to the average level among the boards, which overclocked our test processor to 4.5 GHz.