70C is not bad on a GPU card being worked hard. You have done a good job ruling out so far BTW.
In addition to the nVidia driver, I would update the BIOS to the last revision for the MB. Then I would update all the drivers starting with the chipset driver. Then with the system up to date if you are still getting hammered I would say it is time to contact nVidia and the game maker about this issue. They cannot blame it on your setup. Your GPU is more than adequate to play that game. This strikes me as a bug.
You can play the game without the GPU so the rest of your unspecified system seems adequate.
If you opened up the side and blow air from the fan into the case that way I would be more inclined to dismiss a cooling issue, since the rear fan hole is for exhaust not disruptively blowing cool air into. Of course installing a fan out of there might help keep the card cooler.
You could try stressing the GPU independently with some dx apps:
Video Card Stability Test (Freestone)
Additionally this can test video RAM and card. (trial is free)
These are GPU testing apps. There may be better (newer) ones now (DirX12). If Unturned uses DirX more than OpenGL or vice versa then you know which to use (pick one).
MSI Kombuster = GPU
Heaven = GPU (DirX11)
OCCT = CPU + GPU (PSU load test)** dangerous on low quality PSUs
AvP Benchmark (GPU, DirX11)
Furmark = GPU (OpenGL)
Tessmark = GPU (OpenGL)
If you cannot get the card to fail similarly then that points to a bug in the game. Usually both Nvidia and the game maker are interested in eliminating those.
If you can get the card to fail then I would first suspect heat (running HWMonitor in the background keeping a log file can help if you stop before the hang to save the log). If it is overheating (consult nVidia/ASUS) then adding a exhaust fan to that open port may fix or buying a better designed gaming case. If not heat then maybe PSU or card defect.
Edited by Fascist Nation, 16 May 2016 - 10:49 AM.