Sorry for OT but I had a quick chance to test 970 against 1080, didn't have time to find absolute sweet spots but here are some equihash numbers:
Nowadays there is no gpu that can handle every algo well, here is an example where that crappy 970 (above) beats 1080 (below):
Out of curiosity - what algo is that? 1080 should be superior at every aspect and I am very surprised to see that.