Sandy Bridge processors manufactured with progressive 32 nm process have already set a new energy-efficiency standard. However, our today’s heroes – Core i3-2120 and Core i3-2100 – are a little different from those second-generation Core processors, which we have discussed before. Dual-core processors use a slightly different reduced semiconductor die with almost half the transistors. So, it seems quite logical to expect these processors to show even lower power consumption readings. Especially, since their TDP is set at 65 W, while quad-core Sandy Bridge processors have their TDP at 95 W.
Of course, we performed a few practical tests. The graphs below 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 LinX 0.6.4 utility. We enabled all the power-saving technologies for a correct measurement of the computer's power draw in idle mode: C1E, AMD Cool'n'Quiet and Enhanced Intel SpeedStep.
Strange as it might seem, power consumption of the dual-core Sandy Bridge CPUs is at the same level as the power consumption of their quad-core counterparts. Obviously, the power-saving technologies in the new processors have become so advanced that idling computational cores barely use any power at all. At the same time, the power consumption of the entire LGA1155 platform in idle mode is very close to that of LGA775 systems, which remained among the energy-efficiency leaders in idle mode for a long time due to their simple design and structure.
However, under maximum load all our expectations come true. Core i3-2120 and Core i3-2100 turns out the most energy-efficient processors in our today’s test session. All this makes dual-core Sandy Bridge CPUs a extremely appealing choice for an HTPC system, because when their integrated graphics core is disabled they consume anywhere between 5 and 35 W depending on the workload. However, keep in mind that Intel also offers even more energy-efficient processors (although they are also more expensive) that belong to the T series.