noxinum :
I did lower the speed fan and so it hits 70% only when the GPU is at 65°C but now at 56°C it sits at 50% fan speed and makes no noise at all.. my gpu doesn't really go pass the 60°C even while playing Witcher 3 max settings and OW ultra settings. I got 3 fans for intake and 3 for exhaust ( if you count the 2 from the water cooler for the CPU )
Sounds nearly identical to mine. These cards are already OC'd pretty close to max what air current cooling can provide. I personally don't believe a few extra mhz is worth the added noise levels.
I've read perhaps hundreds of reviews for the various 1080's on about a dozen sites. Once they get around 1.8-1.9ghz there's usually only 1-2fps difference for any of the cards so noise/temps/price are the only real things to keep track of.
I did do an experiment in the fall and had my tower directly under the A/C vent in the room. Cranked the card fans to 100%, lowered the A/C to around 63f and was able to keep the clocks around 2.1-2.2ghz all day at ~60c. It was noisy and used what was probably a ridiculous amount of electricity. It was only around 2.2ghz I really began to notice any significant gains in FPS.
I've noticed that at 65c they'll usually keep around the 1.8-1.9 mark which works fine for most things.
It'd really be nice if someone came out with a refrigerated air case instead of all these over-complicated water cpu/gpu solutions. Seeing what my experiment succeeded with its obvious just feeding cold air into the case can accomplish quite a bit.