At my power saving set up I use the quiet fan setting and my performance setup i use default fan setting (its loud)
Also I can get 16.1 at like 780w or so, but I cant stay about 16 and get down to 750w.
Its very dependant on each day, as these boards are not consistant. So some days on my power saving mode I can run at 1v but some days I have to run 2. And I have one board that needs 6.
These things have their temperament, I have no idea how is it possible that they work different every day, or change drastically with just a power-cycle. But bitcrap miners are known for getting up on the wrong side of the bed some days.