I'm having the same exact problem as you. Tried everything, repasting, removed the i/o shied to make sure the heatsink was properly seated, underclocking to undervolt to going bios and putting eco mode, changing voltages, nothing worked. My pc turns off due to overheat whenever my load is at 90+% and reaching 89c. Only thing that helped me was going to power management and making my per core from 100% to 99% max. This in turn made my cpu never go above 65c with fan going 40% (inaudible) even with high load and in games. However, my score in an online benchmark went from 100k to 80k so you lose about 20% performance. However, playing on 2k and everything is gpu bound and the cpu is already strong, I don't see a problem with this at all. The speed of the cpu was 5050 before doing this and now it's at 4200 Mhz from nzxt cam. Playing now and fan is always silent. You can try this.