Power consumption has never been AMD's strong suit and it becomes evident when comparing these sub-$100 processors. While the Athlon II X4 630 was regularly found delivering the best performance of all tested processors, it is also by far the most power hungry. The L3 cache of the Phenom II X2 555 processor takes its toll in the power consumption front, with this dual-core chip using more power than the Athlon II X4 630 at idle and just 20 watts less under load.
On average, the Athlon II X4 630 used 52% more power than the Pentium G6950. The Phenom II X2 555 used 39% more, making it far less efficient given the performance that we saw throughout the benchmarking phase. Even the single core Sempron 140 uses more power at idle than the Pentium G6950.