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).
Because of the above described compatibility issues, we had to replace our standard Cooler Master RealPower M850 PSU with Enermax NAXN ENM850EWT. This change in our testbed configuration didn’t have any effect on performance, but it undoubtedly affected the power consumption readings. Both power supplies are very similar in technical specifications, but Enermax NAXN ENM850EWT turned out 1-3 W more energy-efficient than the previous one. In order to be able to use the previously obtained results, we decided to make up for his efficiency difference by adding 2 W to all power readings taken off Gigabyte GA-Z77X-UP4 TH and Gigabyte GA-Z77X-UP5 TH mainboards, so that we could still compare their results against the power consumption of all previously tested products.
Looks like the transition to new component base did have a positive effect on the energy-efficiency of Gigabyte mainboards. Gigabyte GA-Z77X-UP4 TH showed average power consumption, while the power levels of Gigabyte GA-Z77X-UP5 TH were a little above average, but still lower than the power consumption of the Gigabyte GA-Z77X-UD5H-WB WIFI with similar functionality.
During overclocking the power consumption of Gigabyte GA-Z77X-UP4 TH remained at the average level. However, we should definitely praise Gigabyte GA-Z77X-UP5 TH for showing unexpectedly low power readings during maximum CPU utilization. It is comparable with what other mainboards in the 4.5 GHz overclocking group showed, although there is still room for improvement in idle mode and under minimal operational load.