One of the advantages of integrated systems we’re discussing in this review is that they have low power consumption and heat dissipation compared to PC configurations with discrete graphics cards. Integrated platforms are often bought with the purpose of minimizing running costs and find their place in a compact computer case. That’s why the developers of processors with integrated graphics cores focus on power-saving features, which is indicated by low TDPs. For example, the TDP of the Core i3, Pentium and Celeron series is limited to 55 watts. AMD’s APUs are somewhat worse in this respect as their TDP is set at 100 or 65 watts, depending on the particular model. However, the TDP parameter itself is just a general requirement to the recommended cooling system. Things can be different in reality, especially as junior processor models should actually be more economical than their senior cousins.
To find out more about the power consumption of all tested processor models from the APU category, we performed a round of special tests. The new digital power supply unit from Corsair – AX760i – allows monitoring consumed and produced electrical power, which we use actively during our power consumption tests. 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 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 1.10.4 utility to load the graphics cores. Moreover, we enabled Turbo mode and all power-saving technologies to correctly measure computer's power draw in idle mode: C1E, C6, Enhanced Intel SpeedStep and AMD Cool’n’Quiet.
All the processors and platforms have the same level of power consumption when idle. Each modern processor can switch to a special power-saving mode and consume just a few watts. It is the power requirements of other system components and the efficiency of the mainboard’s voltage regulator that go to the fore, concealing the actual consumption of the processor.
The single-threaded computing load helps rank the processors up according to their power consumption. The Core i3, Pentium and Celeron series are rather economical whereas the Socket FM2 solutions need considerably more power. The high power draw of the AMD A10-5800K must be pointed out: this APU was released by AMD in order to achieve maximum performance, so there was no talking about economy.
At peak x86 computing load we can clearly see the differences between solutions from the two processor manufacturers. Intel’s are more economical than AMD’s. Even the slowest dual-core A4-5300 and A6-5400K need more power than the Core i3 which are much faster in sheer performance. The senior A10 and A8 series with a specified TDP of 100 watts are downright uneconomical compared to their Intel opponents. Their configurations need almost twice as much power as the LGA1155 platforms although their performance isn’t any better. Well, the 65-watt quad-core Trinity products are not really energy-efficient, even though do help you save 20 to 30 watts at high loads compared to their 100-watt cousins.
AMD’s solutions are no better when it comes to 3D loads, but their high power consumption is justified in this case by their higher performance.
There are no changes when both the x86 and graphics cores are in use concurrently. The A10-5800K and A8-5600K processors with a TDP of 100 watts need 30 to 50 watts more than the others in practical applications. The platform with the Core i3-3225 (Intel HD Graphics 4000) only needs more power than the Socket FM2 systems with dual-core Trinity APUs. Thus, the Trinity with a TDP of 65 watts is hardly economical even compared to the Core i3-3225. Intel’s solutions obviously offer better performance per watt. Besides being more energy efficient, they are more versatile in terms of installing them in cramped systems cases with low-wattage PSUs and low-profile coolers.