I have seen the increase on my pool, GTX1080 is working now at 1.38 MH/s* for 4 days and steady as rock.
More details please on actual core and mem clocks as well as power limit. I have two different GTX 1080 - an EVGA Founder's Edition and an Asus ROG Strix - and the best
consistent speed I can attain is 1230 kH/s, and even this is in question based on the cumulative earnings over a 4.5 hour period on a high volume Neoscrypt pool that I trust.
* - units corrected to MH/s.