I have a Predator helios 300 315-51 its a good laptop and serve me for a lot of years now and this thing starts to cpu throttle at 85 degrees like if any spikes happen at 85 degrees it will throttle to 2200 mhz on the cpu if you use predator sense having the fan control at autothe fan ran slower because im always at below 85 degrees with coolboost on. And tried everything undervolt change paste to PTM 7950, ptm 7950 did wonders and made me realize the thermal throttling limit of this laptop because of how stable the paste is. I know the new helios have better cooling now because of the cpu and gpu are far apart now I wish I have the money for it though. Sorry I had to rant I got too carried away maximizing my laptop and wasted a lot of time just to get the same problem all over again because of 85 degrees limit.
[Edited the thread to add issue detail]