Clarkdale's Efficiency: Core i5-661 Versus Core 2, Athlon II, And Phenom II

Power Consumption

We didn’t use a high-efficiency power supply, nor did we bother to optimize anything. Yet, the DH55TC/Core i5-661 system delivered very impressive results. Idle power at 30W was as low as we could go with a Core 2 Duo E7200, a G31 motherboard, and a high efficiency power supply around one year ago. Now, we’re hitting this low idle power level just with regular components. A high-efficiency power supply, energy-efficient hard drive, and some voltage modding could easily bring a similar system to roughly 25W idle power. The amazing part is that it would still beat any Core 2 Duo system.

The two AMD systems require significantly more power at idle. This is where the low-power Athlon II X2 240e shines compared to the regular Phenom II X2.

The difference at peak power is not as large as at idle. Still, given that the new Core i5 dual-core system delivers significantly better performance, the drop from 92W to 83W represents a roughly 10% reduction.

The Athlon II X2 240e’s 45W TDP is a huge advantage here, greatly narrowing power consumption gap against the Core 2 Duo machine. However, the Phenom II X2 still requires much more power. The difference is at least as large as the Core i5 661’s idle power requirement.