What are you mining to get that?
But, seriously, $15 a day per card? For a few days with a real exchange?
with 2 real exchanges
SPR and NXS I guess. I got more than 18$/day per 1080Ti
Are these any good now?

68 coins on 6x1080Ti rig per two days. It is approx 17$/day per each single card. It is awesome.
What kind of algo is that? 104% power limit instead of less than 100%? reduced memory speed and increased GPU speed? Is there even any point in reducing the memory's speed?
It's not like you'll get lower tempratures or less power consumption because of the memory's speed.... or so I know.