How do these CPUs compare for power usage?
In contrast to our previous comparison, the Pentium G6950 power usage is much lower. The reason for this likely lies with motherboard selection, suggesting that the Gigabyte H55M-USB3 is a power sipper. When the CPUs are overclocked, idle power is similar, but the Phenom II X2 555 requires 40W more under load. After the Phenom's four CPU cores are enabled, it requires another 40W at load. But with a total draw just under 250W, it's not exactly a power hog.
First, note that there are no quad-core Phenom II X2 555 results here--our temperature-monitoring software does not work when the CPU's dormant cores are enabled.
Idle temps look great across the board, thanks to low-power optimizations like Cool'n'Quiet, Enhanced Intel SpeedStep Technology, and C1E support (especially on the stock Pentium G6950). But under load, we can see some major differences. Note that the Core i5-750 is employing Intel's stock cooler, while the dual-core models benefit from Cooler Master Hyper TX 3. The overclocked Pentium G6950 is getting a lot hotter than the overclocked Phenom II X2 555, while it looks like the high clock speed is trumping the Phenom's increased voltage in this respect.