Game shutting down pc

What do you mean by "more demanding games"? ONI is using really heavy power on the CPU, and there mostly on one core, but near to nothing on your GPU. Most games are using heavy GPU, and fair share of the CPU. So, you cant compare in general.

5-10minutes sounds most likely heat problem. Dou you monitor your CPUs heat?

Second possibility would be your power suply, shutting down, when the CPU runs at full power. (Or the VRMs on your motherboard break down, due to heat or age)

In General, a game should not be able to shut down your PC at all. It may freeze, it may crash, but shutdown is either a serious hardware problem, or a windows issue. 

Its clearly possible, your PC runs fine with other games, but cant handle ONI. 

You should check for the temperatures first.

What hardware are you using?

I have this problem too, after last upgrade my computer shutdown after 3 minutes of game.

I play other games like GTA V and I never get this problem, before the upgrade I never get this too.

Some times, when the game autosave the computer simple shutdown. I check GPU temp in the momment of shutdown and was only 51ºC all time.