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’s power consumption grows up depending on the number of active execution threads in LinX (both at the default and overclocked system settings). The mainboards are sorted in alphabetical order on the diagrams.
We often point out that on many mainboards certain power-saving technologies are disabled by default. This time we decided to illustrate our discontent with this issue with numbers. We measured the power consumption of test systems in idle mode with default settings and then with all power-saving technologies manually enabled.
We have already mentioned that all power-saving technologies work correctly right from the start on Gigabyte GA-990FXA-UD5 that is why forcing them to “Enabled” and switching the “AMD C1E Support” from Auto to Enabled didn’t affect the system power consumption readings in any way. This is a definite advantage of this mainboard, but there are drawbacks, as well. We mentioned that the BIOS of Gigabyte mainboards lacks functionality for proper configuring of the proprietary power-saving technologies, such as dynamic change in the number of active voltage regulator phases depending on the CPU utilization, for example. Most mainboard makers have already implemented features like that in their products, while there is nothing like that on Gigabyte boards yet. Therefore, you won’t be able to additionally lower the power consumption in any way.
Speaking of the power consumption in nominal mode under heavy load, we uncovered one strange defect in our Gigabyte GA-990FXA-UD5: its power consumption under only half the load of 4 threads turned out higher than under full 8-thread load.
We repeated the tests twice to eliminate the possibility of a random fluke, but the results remained consistent. At the same time you can notice that there is nothing like that with the top model - Gigabyte GA-990FXA-UD7. There must be a problem with the Turbo technology that increases the processor frequency and core voltage.
When we compared the consumption rate of our Gigabyte GA-990FXA-UD5 against the competitors in the overclocked mode, it looked better not only because it couldn’t overclock the CPU to its maximum and therefore the processor Vcore was lower. It makes more sense to compare it against Asus M5A970 EVO and MSI 990FXA-GD80, which also hit only 4.3 GHz. In idle mode and under minimal load Gigabyte board consumes about the same amount of power as the other two boards, yielding a tiny bit to the MSI product. However, under maximum load it is significantly more energy-efficient.