14nm is two full nodes after 28nm. Just like 65nm was 2 full nodes after 130nm. When you add architectural advancements as well as finfet, 1/4 power consumption is a very reasonable target. Just compare a 130nm northwood to a 65nm conroe. That was 1/4 the power consumption for the same performance. Hell, it was probably better than that. You could literally run two 65nm conroe cores at the lowest possible frequency and voltage, and its performance would be greater than a 3.2GHz northwood. Also, the timespan is about the same in each case as well. The 3.2GHz P4 was launched in mid 2003, and conroe 3 years later. The first 28nm smartphone SoCs were launched 3 years ago. It all fits well within expectations of a full 2 node jump.