I've had better luck with higher clocks (sometimes drastic) with dstm. Course every Rig, PC and Software is different with each configuration slightly. Just to see if there was a major difference again, I tried the EWBF with the --fee 0 option on one of my 1060's. I was getting 305-308 sols average. DSTM same settings 322 sols average. So with a 6.5 dev fee I'm getting 8-11 more sols during mining. Not much but quicker but still in the positive column to the tune of a few extra bucks a month (given the markets current drop in price).
Well, my GTX 1080 that is in my daily rig is watercooled. Doing 2000Mhz with 0.9v(85% TDP that would be), at max 37C. Efficiency over 4sol/w... I tried 2200MHz, which my card can do ez, but not getting more sols to be honest...
Thats nice! I know my 1080TI can hit upwards of 800Sol around 1850-1900Mhz (it moves around) at 90% TDP if the temp is sub 50C. Yeah my efficiency rides around 3.3-3.4 with the card on average. Still good in my book. Way better than when i started at only 680 Sols @ 100% TDP

It ends up being more efficient than my 1060's I got but least I topped out what my 2 small rigs can handle for cards and temp.
Maybe I should look back into water cooling again. Use to do it ages ago(14+ years), maybe its time to investigate it again.