In the last couple of weeks, my late 2015 27" 395X 32Gb RAM 4GHz i7 iMac is just shutting down on me regularly. This happens in Windows bootcamp as well as macOS, and is always when I am playing demanding games, e.g. Deus Ex Mankind Divided, DCS, etc. I am vey concerned that this is due to overheating. See attached graph from iStat. Through the period of this graph, I was playing Deus Ex MD. The dips are where the iMac went to sleep! Any thoughts on this?