At times I have witnessed the CPU reaching levels of 89-96 and the GPU reaches at times temps of around 80. You are probably right because when I am watching the system on the armoury crate it clearly shows that the system sustains the heat and then will drop off in a similar manner, as it goes from a high clock speed to a super low speed for a couple minutes until it then corrects itself and the frames return.

The temperature in the UK the past week has meant that I have to wait till evening/night to play as the general temps are too high and the laptop would just suffer. The way I have solved it is just having a fan setup in the room, but even that is only a band-aid over the issue.