Most recently tested games were Vanquish, DOOM (2016) and Painkiller all at 1440p though this seems to effect all games.
Issues were not present with previous Nvidia GTX 1060 6GB
Task manager reports a '3D' spike during desktop crashing
Edit: limiting the FPS to 150 via Radeon settings target control seems to reduce the minimising frequency, though these are replaced by more standard freezes and hitching.
Similar issues seem to arise from a bad overclock from what i've read but my card has not been overclocked