Gpu 78-80 under load, playing pubg in 2k.Idle or under load?
What temperatures is your CPU hitting?
How is airflow distributed through your case?
Had fans set at 900 rpmAre your fans increasing RPM accordingly as it heats? Does increasing your fan RPM manually improve temperatures?
The thermal throttle point for a GTX 1080Ti is around 84 degrees, so you're not doing damage, but ideally you'd want it cooler.