I have a Dell inspiron (Not sure which exact model), it has intel core i7 and AMD Radeon R5 M335, running Windows 10.
If I leave a game running to idle, then the computer freezes, I can't do alt-ctrl-delete, screen goes dark, even the power button stops responding, the only way to unfreeze it is to remove the battery and unplug it.
This only happens if the game's process is maximised, if I alt tab to desktop, leave the game running in the background, and let it idle, nothing goes wrong.
I do not have the computer set to sleep automatically, that's not the issue here.
It is running on high performance. The games are running full screen.
The issue happened with Dark Souls, Witcher 3, and Warframe.
I don't know how long it takes it to freeze, but no more than 5 minutes.