I just bought Galax GTX 1060 6GB and indeed its memory using Hynix. I've tried overclock / underclock and maximum results are 300-327 Sol/s in Equihash. My settings are:
power limit 90
temp limit 75 (manual)
core clock +225
mem clock +575
fan 60 (manual)

power usage 105-110W (ewbf)
eficiency 2.8-3.1 Sol/W (ewbf)
temp 66-70

UPDATE:
efficiency >3 Sol/Watt, reduce power limit to 85