Question My games are crashing after running for like 5 - 10 min even if my PC tests are all OKAY

Jun 26, 2019
PC Spec : -

MOBO :- Asus ROG Maximus IX Formula Z270
CPU - core i7 7700K
GPU - Asus ROG Strix GTX 1070 OC
RAM - G.Skill Ripjaws V 3000Mhz 8GB*2
PSU - Corsair HX1050W Modular
Cooler - NZXT Kraken X52 Liquid Cooling
HDD - Seagate 1TB*3
Monitor - BenQ 24" XL2420T 120Hz 1920x1080
OS - Windows 10 x64

About 2 days ago the problem started. All my games are crashing after playing for like 5 - 10 mins. If I put them on low settings then somehow they are running but whenever I put them on Ultra/High settings they crash. Even when I ran a latest game (Shadow of Tomb Raider) it said it can't run on my GPU, please lower your settings to run it. But I already played that game somedays ago on Ultra Settings
I thought it was GPU problem so I took the GPU out and went to my friend's house to test it. And it ran smoothly without any issues. I played in his PC like 2 hrs with Ultra maxed out 1440p and no problems at all.

I checked everything Prime95 cpu tests okay, memtest 86 memory tests okay, motherboard errors okay, HDD tests okay, Temperatures are okay. Scanned for malware and viruses but everything was clean. Reinstalled windows 10. Even tried breadboard to check for any short circuit issue but was fine.

Temp :-
CPU (Stress Test) - 60 - 70 degree C
CPU (Idle) - 34 - 40 Degree C

GPU (Stress Test) - 60 - 65 Degree C [*Crashes after some sec]

Normaly windows is running fine without any issue. Only issue is when I play my games. And another strange thing is. When I bought back my GPU from my friend's house after testing yesterday it ran okay again in my PC and I thought may be the problem was solved but today it started again.

I have no idea where the problem is. I have been trying to figure out that. Please help me !! T_T
Jun 26, 2019
So, I found something out today after tweaking for 3 to 4 days. On ASUS GPU Tweak II I lowered my my Boost Clock to 1810Mhz (Default Boost Clock = 1835Mhz) and the Power Target for the GPU to 90% (Default = 100%) and for 3 hours its running fine while gaming without any crashes.

Whenever I set everything to default settings it starts to show problems again. So, my question will be anyone knows why is it happening cause I have been running this card on default settings for 2 years now and suddenly I have to underclock it to run my games now. Is it my PSU or the GPU is dying ? Any suggestion will be helpful.