My GTX 980 Overheats on certain games?

[xWingamer]

So, for months now my pc has been going blank after playing ark survival evolved and fortnite causing my computer to crash. My guess was the graphics card overheating although I was not sure til I got HWmonitor and speed fan to monitor the heat of my pc. I was able to conclude the temperature of my gtx 980 would go up to a max of 70 C until it would crash while my AMD FX-8350 4.0Gz went up to similar temperatures due to my water cooling most likely, my guess was the radiators being broken, so I replaced one of them to make sure it wasn't the radiator as well as the pump. My guess is that my mother board is at fault because it had a history of overheating and turning off on my old pc in which I upgraded from. But just incase I wanted to ask other people on their opinions. My pc is able to run fortnite and ark for aproximity 1-2 hours while it run games such as league of legends, warframe and tf2. Sorry, I would have more information but I forgot the motherboard name and my power supply is a crossair 650w. My water cooling system has 1 pump and 2 radiators which cools the cpu and gpu

[Quadriplegic]

70 C should not cause the computer to shut down. 

I would look at motherboard first. Maybe your VRMs are getting too hot?

[Froody129]

Does your GPU waterblock cover the memory/VRM area?

[Biggerboot]

Does the computer completely power off or does it crash (blue screen, game exits/errors out, etc).

I would try a different PSU first especially if the computer is powering off entirely.

[xWingamer]

The waterblock coves everything. My computer just powers off completely no blue screen, game exits or errors. I am looking into the cpu because Hwmonitor tells me that the cpu is going up to the 70s+ so as of a guess, it may be due to the water becoming extremely hot making my cpu hotter than it should be.

[Snipeon]

From what I could see, nope, it isn't a temperature problem with the CPU/GPU. You may wanna check for:

1. Leaks in your water cooling loop.

2. Dust buildup in your case/components.

3. Whether it's your PSU overheating or not.(May be related to dust buildup in there)