Regarding the possible audible noise because of power spikes on PEG: it is not really about cheap MB, but about using analog audio out of MB, and not anything digital, right?
Also, about overclocking: I think reviews of all these new generation nVidia and AMD cards should include average clock that cards operated when doing all game benchmarks. Official boost clock numbers are a bit useless, because AMD cards run games at below boost clocks, and average for nVidia GTX1070 is above boost clocks. Having just official boost clock numbers make it difficult to evaluate overclocking potential and make real gains look much bigger or smaller than expected.