Why bother guessing? Without knowing exactly what they did and without new reviews we won't know.Not even the FE 1080 now they've fixed the fan curves - for some dumb reason the early review 1080's had a really, really passive fan curve so did drop off their boost clocks.
(So add a bit of noise to the review measurements.).
No idea about the 1070's. Not really a great idea to buy an FE anyway - the better AIB coolers will be notably quieter for the same level of cooling performance.
Just screw the fe cards anyway. They're terrible. Get a real cooler and enjoy the far superior cooling and overclocking as well as usually cheaper prices than the fe edition. Just wait for a good aib card, never compromise on your cooling solution.