"This results in chip manufacturing quality being distribution based - a wafer will come out of production with individual chips of varying quality, with some chips operating at lower voltages or lower leakages than others, and other chips being altogether defective. This is colloquially known as the "silicon lottery.""
"Wrapping things up then, where do we stand? The short answer is that all we know is that we don't know. What we know is that there isn't enough information currently out there to accurately determine whether the TSMC or Samsung A9 SoC has better power consumption, and more importantly just how large any difference might be. 1-on-1 comparisons under controlled conditions can provide us with some insight in to how the TSMC and Samsung A9s compare, but due to the natural variation in chip quality, it's possible to end up testing two atypical phones and never know it."