AMD’s E series and Intel’s Atom processors were originally developed for economical computers, so low power consumption is one of their key features. A Celeron, especially based on a 32nm Sandy Bridge core, doesn’t seem fit for energy-efficient computing, but the Celeron 847 has a specified TDP of 17 watts, which is comparable to AMD’s processors with Bobcat architecture. Is it really so? Can a slowed-down Sandy Bridge really ensure high performance while being comparable to specialized products optimized for low power consumption?
In order to answer all these questions we performed some power consumption tests. We used a new digital Corsair AX760i PSU that allows measuring the full consumption of each system (without the monitor) as measured at the PSU’s output. It is the sum total of the power draw of each system component. The PSU’s efficiency is not counted in. The CPU was running a 32-bit version of the LinX 0.6.4 utility. We used FurMark 1.10.4 utility to load the graphics cores.
Without any work to do, every modern CPU switches to a special power-saving state in which it consumes just a few watts. In this case, the other system components and the efficiency of the mainboard’s voltage regulator mask the CPU’s consumption, which must be why the Celeron 847 based platform turns out to be the most economical when idle. It doesn’t differ much from the systems with Atom D2700 and E-350, though. The LGA1155 mainboard with Celeron G1610 needs much more power because mini-ITX LGA1155 products feature a versatile voltage regulator which supports different CPUs and even allows to overclock them. Its efficiency is low at low loads, so the Celeron G1610 based configuration is inferior to the mainboards with simpler and more economical voltage regulators in this test.
At full computing load the Celeron 847 based platform needs as much power as the AMD E-350 based one. The Atom platform is expectedly more economical because the Atom D2700 has a specified TDP of only 10 watts. The Celeron G1610 platform, which is not energy efficient at all, needs one third more power.
The Atom D2700 is the most economical again when it comes to gaming but its 3D speed is far from brilliant. The Celeron 847 is ahead among the CPUs with more or less acceptable 3D performance. It is almost as economical as the Atom D2700, unlike the AMD E-350.
At high mixed load the Brazos and the Celeron 847 based platforms are again comparable in terms of power draw. So we can see that the Core microarchitecture really becomes economical if its voltage is reduced. Although it can’t match the Atom, it equals AMD’s Brazos-based solutions in this respect.