Unfortunately, AMD A8-3870K processor is not one of the energy-efficient products and its TDP is declared at 100 W. Pentium and Core i3 processors has typical TDP of 65 W. However, it doesn’t mean anything in our case, because Intel processors have to be bundled with faster graphics cards in order to offer comparable performance. Therefore, the actual power consumption readings are of great interest to us.
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 utility. The graphics cards were loaded using FurMark 1.9.1 utility. Moreover, we enabled all power-saving technologies to correctly measure computer's power draw in idle mode: C1E, C6, AMD Cool’n’Quiet and Enhanced Intel SpeedStep.
In idle mode Socket FM1 systems boast relatively low power consumption. The system with the integrated graphics core of the A8-3870K processor is the most energy-efficient one here. Although AMD 6000 series graphics cards are quite economical, we shouldn’t completely disregard their contribution to the overall system power consumption.
Under maximum computational load we see that the energy efficiency problems typical of AMD Phenom II and Athlon II processors didn’t go away with the introduction of 32 nm process. Llano processors use the same exact microarchitecture and are completely defeated by Sandy Bridge in terms of performance per each watt of power. A8-3870K based systems consume about twice as much power than their competitors with similar computational potential based on Intel processors.
When we switch to graphics load the advantage of a certain platform type is no longer that obvious. Systems with A8-3870K processor working in its nominal mode turn out a little more energy efficient than similarly priced configurations with Pentium G850 or Core i3-2120. However, overclocking makes the AMD platform more power-hungry than the competitors.
If we load the processor and the graphics sub-system simultaneously, the LGA 1155 platform will again be in the win. Even the most powerful system with a Pentium G850 processor and Radeon HD 6770 graphics card consumes less power than A8-3870K based system with the integrated graphics core only.