Hello @gps05, you should also bring this to the attention to your video driver vendor.
It may be worth looking at lspci | grep VGA and reading what chipset model of your nVidia card you have. If it contains GF108, that means that it is a Fermi generation video card, and the 390 series nVidia driver is the last driver series that supports your video card. If it contains GK107, that means it's a Kepler generation card and you can try a newer driver series.
I would suggest to move over to Nouveau and see what happens if newer proprietary driver is no longer supported for that GPU. It would be slower fps but testing would allow to see if it would change the problem.
If the problem didn't go away when switching to Nouveau then I would suggest you have an OS or hardware related problem. The stuff I would look into first then would be the kernel and bios updates but if there's some other update that it happened after then that you should switch to older or try to roll back.
Nothing extracted yet.
System Information
After I launch any game and some time passes, my system freezes. Sometimes it happens in the main menu. It doesn't always happen while a game is launched. The monitor goes into standby mode and I have to reboot the computer to do anything.
This is also the case on non-beta Steam. I'm not sure if this is limited to Steam games.This isn't related to Steam, it seems.
Happens on any game for me.