Question Gsync causing PC to crash

Jan 18, 2020
Hello guys, I've got a new PC recently and I've been having some issues with it.
Everytime I play a game that is not in fullscreen my PC seems to crash, video just goes out, there is a change in fan RPM and RGB just goes into rainbow mode instead of the setting i gave it. This includes things like visual novels, I play cities skylines in borderless window, as I have many mods and it can take up to about 15 minutes for it to load, so I like watching things while the game is loading and in the background having the loading bar so I can check wether or not it's done loading.
I should also mention that the GPU is overclocked (+600 memory, +200 core clock), I thought this was what was causing it as well, but i reset the settings and same issue was there.
It doesn't include anything that is fullscreen, even though after the PC crashes, the it gives me a directx error in call of duty.
Gsync is switched to fullscreen and windowed mode, however as a last resort i switched it to fullscreen mode only now.
Another thing is that it doesn't crash immediately it can take anywhere between 30 minutes and a few hours. (no it is not temperatures either I've done a few stress tests and keep rivatuner on in msi afterburner at all times in games so I can keep an eye out for temps. CPU hovers around 50-65 celsius max, GPU 50-58 celsius max both under load.
However after it crashes, for example if I was playing a virtual novel, if i start it again right away the PC crashes again right away, but if it crashes, i turn off gsync and go in right away it doesn't crash.

One last thing, I tried also overclocking my CPU once, gave it a voltage of 1.325 V on all cores and 4.2 ghz core clock. However when I started a stress test to see if this was stable, CPU temps climbed up to about 115 degrees celsius which scared me and i reverted to default settings in the bios (gave it a clearCMOS as well just for good measure). Now this really scared me and I'm fearful it caused permanent damage as it was wayy past the Tjunction max of the chip, however the PC did not turn off, and I was running a few tests beforehand as well. I ran a full cinebench r20 test while under this overclock and the test ended up with 9900 points so cores did not fail and core clocks , which meant that the CPU was stable to me, only started doing a stress test in prime95 and monitoring with both hardware montior by CPUID and hwinfo. They both gave a reading of 115 degrees celsius after not even a second of the start of the stress test. Online, I saw people who recommend voltages even higher than this so i didn't think there was a problem. However, I am still fearful I have caused permanent damage to my CPU.

That being said, issue does not happen when i turn off GSYNC completely, from my testing so far even though I have not had enough time to test extensively.

Motherboard: MSI MEG x570 ACE
CPU: Ryzen 9 3950x
Cooler: Corsair h150i pro (with LL 120 fans instead of stock)
GPU: Nvidia RTX 2080ti with driver 441.87 (latest) (tried uninstalling and re-installing fully)
Display: LG OLED C9 55inch (updated firmware to work with gsync)
RAM: Corsair LPX 64 GB 3200 mhz CL 16
PSU: corsair RM1000x
Storage : Corsair MP600 1TB, Samsung 860 EVO 2 TB, Seagate Ironwolf 4TB
If you actually read all that thank you so much, I really hope someone can help, because I've been saving money for years for this moment and I'm not able to enjoy it properly.

Thank you so much