See if you can manually adjust your case fans.
On one pc I use a program called "Fan Speed" and crank the fans up really high while gaming, I use a headset so sound isnt an issue.
By default windows wants to run your fans super low and will just throttle your CPU at 82C, so it shouldnt go any higher then 82C, but u losing performance.
Speaking of which, please tell me your frame rate you play at, and how deep do the fps drops go?
I have a GTX 1070 and have to lock around 72-80 FPS or I get big frame drops regularly.
my CPU is I7 4790(non-k)