The performance differences between the tested Socket FM1 mainboards are no significant enough to consider them the only argument justifying the mainboard choice. There is another parameter that is much more important for the Mini-ITX systems – power consumption. This parameter determines how quiet and energy-efficient the compact computer system is going to be. Moreover, even the slightest difference in power consumption may have very serious consequences for miniature systems: the need for an additional fan or a higher-wattage power supply. Therefore, we paid special attention to power consumption tests this time.
The thing is that mainboard makers can seriously influence the power consumption of systems built on their products. The key factor here is the efficiency of the processor voltage regulator circuitry. This is where the skills of the engineering team can really shine.
The graphs below (unless specified otherwise) show the full power draw of the computer (without the monitor) measured after the power supply. It is the total of the power consumption of all the system components. The PSU's efficiency is not taken into account. The CPUs are loaded by running the 64-bit version of LinX 0.6.4-AVX utility. We used FurMark 1.9.1 to load the graphics core. Moreover, we enabled all power-saving technologies and Turbo Core mode to correctly measure computer's power draw in idle mode.
The differences between the testing participants stand out even more in the power consumption tests than they do in performance tests. Even though all four boards have four phases in their processor voltage regulator circuitry, their actual performance is completely different.
ASUS F1A75-I Deluxe is the energy-efficiency leader, which is quite understandable. Its processor voltage regulator circuitry uses innovative digital-analog design, and besides, this mainboard has a special EPU processor managing the number of active phases in order to improve the voltage regulator efficiency. As a result, ASUS F1A75-I Deluxe based system consumes a few watts less than the competitors in idle mode as well as under diverse operational loads. This is particularly impressive considering that Asus mainboards has a lot of additional onboard controllers and is the fastest of the four boards.
However, it is important to keep in mind that if you are really concerned with the energy-efficiency of your Mini-ITX system and do not need a powerful graphics core, then it would make much more sense to give up Socket FM1 platform altogether. Even with an energy-efficient AMD A8-3800 65 W processor inside its power consumption is still higher than the power consumption of LGA 1155 platforms with similar computational performance. And taking into account that Intel can also offer 35 W CPUs, the superiority of solutions from Intel becomes undeniable.