Those temps a good now - running small FFTs at your voltages using that cooler.I've reduced the RAM to 2933 and it seems to be running stable with a 3.9ghz OC, max temps still 75c with small FFTs,
The Gigabyte Extreme 1080Ti will get toasty and rids itself of heat very effectively - so the heat will have to go somewhere.Will leave it for now until a new BIOS update it out, problem is though when I game and the GPU is in full use it creates more heat which raises the temps?
What case are you using? - this is where a quality vented cooler come into their own.
I would...I'll try lowing SOC now and see if its stable
EDIT: I was slow with posting - but good to read you may be sorted...