The most interesting aspect of the just-announced Qualcomm Snapdragon Wear 3100 chip is the custom designed QCC1110 low-power co-processor. It uses near-threshold design which is pretty cutting-edge stuff, but has a huge impact on power consumption.
Instead of slamming the transistors with enough voltage to comfortably ensure digital operation with plenty of margin, near-threshold designs operate at very low voltage (0.6V in this case) & dangerously close to analog transistor operation.
Near-threshold operation requires tight transistor design, dialed in process control, accurate transistor characterization, & a new set of EDA tools. It's running on the edge of failure w/ minimal margin for error. Everything has to be tight & accurate to stay within that margin.