A few initial observations on the clock behavior of my Asus GTX 1070 FE, in preparation for my testing of gaming performance vs. the 970, 980, and 980 Ti, stock and overclocked.
As background, I've tested multiple 670, 780, 780 Ti, 970, 980, and 980 Ti cards, so I'm pretty familiar with how GPU Boost has worked on these models. The GTX 1070 is different.
Out of the box, it doesn't hold a constant clock speed, not due to temperature but due to both the power limit and GPU Boost behavior. In short, without touching a thing, the GTX 1070 averages around 1760MHz, but it is not a constant clock. With a simple adjustment of the power limit to the maximum 112%, it averages around 1810MHz, again not constant, but consistently higher than completely stock.
In terms of overclocking, the card will accept a +200MHz offset, crashing immediately with 212MHz. That takes it to an average of 2000MHz, fluctuating between 1980MHz and 2050MHz, again with the 112% power limit. Overclocking without raising the power limit makes no sense at all, because the card vastly overshoots its power limit even at stock clocks, operating at 100% nearly all of the time (and consequently dropping the clockrate). I've tested the memory up to +400 (8800MHz), and will probably leave it there, as memory instability is harder to pinpoint and I'd rather focus on just getting to my gaming benchmarks.
More to follow later this week.