Urgent: PC Auto shutdown and boot up again

[xiaonix]

My custom built desktop have been around for say about 4 months or so.. However, last weekend I start to have this problem whereby when I play games after awhile say about 45 mins or so, it will auto shutdown and boot up by itself again, and if I play game again, the cycle repeat. It only happens when I game, but if I surf normally like watch youtube and movies etc, it doesn't happen

Initially I thought it was CSGO issue, however I tried it with GTA 5, the problem also persist.. Anyone know what is the problem and what I can do to solve it ? In addition, my desktop temperature when gaming hovers around 40 - 45 degrees only though, so I don't think it's a critical temperature issue.

PC Specs:
i5 - 4590
MSI H97 Gaming 3 Mobo
MSI 970 Gaming edition
Samsung 850 evo 500 gb ssd
Gskill 8gb ram
WD 1tb HDD blue
Corsair H100i (water cooling)
Corsair RM550 PSU

 

[ZrE0_Cha0s]

try removing ur gfx and use ur mobo graphic and see if u pls CSGO will shut down or not.

 

[Bardiel]

high chance gfx card over heat.

 

[yusoffb01]

Run occt and see temperature when it shuts down.

If not hot then send rma they can test on spot

 

[herman1314]

use msi afterburner's on screen display and check the gpu and cpu temperature, see if either one of them are overheating when you play games.