Hello,
Currently I had build a rig for almost an year now and didn't experience any issues, but suddenly I started experiencing shutdown on highly graphics games like (GTA V, BFV etc.). I had suspected the psu since it was cougar STE 500w which is a low quality PSU, changed it with a cooler master 600W PSU which is the recommended for the GTX 980ti. It still had issues of shutdown, even tried getting a spare GPU GTX 1070 to check weather there's an issue with anything else, but seemed quite working well. So does that mean by GPU has become faulty and won't operate well under stress or it doesn't take enough power to run properly?

Specs:
MSI B450m GAMING PLUS
AMD Ryzen 2600x
Evga GTX 980ti SC ACX 2.0
8gb ram stick ADATA XPG
Samsung 500gb SSD m2
Cougar mx330 PC case
Cooler master version 3 PSU 600w

Here's the voltage values after benchmarks (Valley Benchmarker 1.0) :


CPU:


GPU: 


That's my current settings in EVGA Precision X1: