Tom's Hardware writes:
"We published an interesting article last month: "Intel Power Consumption Then and Now" compared performance, power requirements and performance per watt of four different Intel processors. We started with an old Pentium 4 and went all the way up to a Core 2 Quad, and we ran all tests and benchmark at the same 3.0 GHz clock speed. The results were amazing, finding that current processors not only offer significantly more performance, but also much better energy efficiency than the old Pentium 4/D generation.
Of course we also wondered: shouldn't this also apply to AMD? Typically, we start any comparison alphabetically, which would have led us to analyze the performance per watt development of AMD first."