Computer Started Freezing During Graphically Intensive Games

[Abecto]

About a month ago, I started playing War Thunder. Everything was fine, but then one night the game started freezing. My computer would totally freeze either after a few minutes of flight, or immediately upon entering a match. The computer also sometimes immediately shuts off as if the power was totally disconnected. It's either this or a total freeze and a hard reset. I cannot play these games at all. My drivers are all up to date, and other games are not working either. It seems as if the more PC intensive games are the problem. Arma 3 and 2 do the same thing. A few moments after launch there is a freeze or shutdown. My PC temps seem normal, never exceeding 40 C. Is something failing, any help is greatly appreciated.

This is my Speccy.
Summary

Operating System
Windows 7 Home Premium 64-bit SP1
CPU
AMD FX-8350 29 °C
Vishera 32nm Technology
RAM
8.00GB Dual-Channel DDR3 @ 936MHz (9-10-9-27)
Motherboard
ASUSTeK COMPUTER INC. SABERTOOTH 990FX R2.0 (Socket 942) 27 °C
Graphics
HP 2011 (1600x900@60Hz)
3071MB NVIDIA GeForce GTX 780 (EVGA) 29 °C
Storage
1863GB Seagate ST2000DM 001-1CH164 SATA Disk Device (SATA) 27 °C
Optical Drives
ASUS DRW-24F1ST a SATA CdRom Device
Audio
Logitech G930 Headset


UPDATE: Computer just froze after posting this, event viewer just says Kernel-Power: System

 

[Vynavill]

Feels like a power supply issue. Model and wattage?

 

[Abecto]

XFX Core Edition PRO850W

 

[Vynavill]

Hmm, the PSU is a good one...it could be a faulty unit, although it would be weird.

Is anything overclocked in the system?
Are you absolutely sure your temperatures are under control? Use HWInfo or a mash-up between GPU-Z and CoreTemp to monitor them, as speccy isn't exactly....accurate.

 

[Abecto]

Nothing is overclocked. When I watch my temperatures, they never go over 40. It doesn't seem like heat is building up and then a freeze, the freeze just comes at random.

 

[Vynavill]

For having load temps of 40 celsius degrees, either the room is frozen cold, the PC is water-cooled, or something's wrong with readings...
Even 30 at idle is extremely low, although comprehensible if you're staying at 60hz on such a resolution.

If you have a friend who has a capable PSU unit, ask him to let you try it on your PC. If it still crashes, we know it's not a faulty PSU unit, at the very least...