I have 6 rx480, with modded overclocked + memshift bios. With solo eth mining , they draw 77W power ,core voltage at 950mV.
However, when they dual mine , their power consumption rise to 110W+, core voltage drops below 935mV, at 60C temp .Will this damage my gpus in the long run?
As long as you have a high quality psu and maintain this 60c you should be fine , you should get out the max of your cards profit as long as you are in the safe side.