Some really interesting info on the new boost technology and how it relates to performance and the overclocking implications. I recommend reading these pages in full to get the whole idea:
http://www.techpowerup.com/reviews/NVIDIA/GeForce_GTX_1080/29.html
The gist:
"
This means that for the first time in GPU history, lower temperatures directly translate into more performance - at any temperature point, not only in the high 80s."
This is going to have big implications on overclocking and cooling. It basically means that even if you've got your clocks set high, if your temps aren't under control, you're not going to see the performance gain you could. Meaning that cooling and temperature control are going to be KEY, more than ever before, in getting good overclocking performance.
And then there's their overclocking results, which actually do mirror what Nvidia said the 1080 could do:
http://www.techpowerup.com/reviews/NVIDIA/GeForce_GTX_1080/30.html
They were able to achieve a 2100Mhz boost clock, giving them a quite nice performance boost at the same time.
3rd party card situations are going to be FUN to watch. Those with the best cooling solutions are going to really get an advantage.