About two weeks ago I started having problems with what I suspect is my GPU. In some games, particularly in VR, I'll randomly get a black screen and I hear the fans ramp up to pin at 100%.

I did some googling and testing. Reseated video card, checked power cables, and even ran benchmarks to test if anything else could be causing the problem.

System specs are:
i7 8700K
32GB RAM @ 3200MHz
2080 Ti XC Black
Seasonic 750W PSU
Everything at stock clocks.

Here are a few things I noticed when trying to figure it out. I can run things like Furmark to peg the gpu at 100% power draw and full load, no issues for 30+ minutes. I can play games that don't load it heavily, like league of legends, with no issues. I tried playing Skyrim for a bit as a test, and here's where it gets a little weird.

Once the card sits at 80°C for a few minutes, system either restarts, or more often black screen with fans at 100%. Same result with VR games.

My CPU gets up to the high 40s even under heavy load and no unusual motherboard temps, so I know it isn't a case airflow issue.

So far the only solution that seems to be working for me has been to lower target power and temp in Precision X1, but I feel like making my GPU start throttling early defeats the purpose of having bought it in the first place considering its price a year ago. I'm just sort of confused as to how this issue just suddenly came up after nearly a year without any problems.

I'm away from home for the next few days for work, but hoping to get further troubleshooting tips to try out when I return. I do still have to try the debug mode in the nvidia control panel to run at reference specs, and will update if that fixes the issue. Thanks in advance everyone.

Its definitely your drivers, I would go to NVIDIA.com and click driver updates and see which 1 you have, if its up to date uninstall it and reinstall it, I recently had to do exactly that and has worked right since! you also need to download evga precisionX and take control of your fans 
 

Cant grab a new 1000watt or more PSU?

Not saying that 750watt isint enough.. more headroom for happier psu.

Maybe the psu is a few years old and not putting out the watts it used to?

Maybe you can find one locally and you can return it if it's not the issue.

80c is ok as the max allowed temp is 89c.

Okay so, I made it home yesterday, and decided to try running the card in debug mode through the nvidia control panel before swapping out the power cables. As of right now everything seems to be working this way just fine. I'll try turning debug mode back off later today to see what it does.

Time to pull that card apart and reapply thermal paste and pads. Sometimes you just get unlucky and get poor application from the manufacture. I remember my RTX 2080Ti Founders really struggling once it got past 72C with heavy GPU throttling to keep the temps down.

Alright so, I was kinda expecting to see something go wrong with it but, I just managed to run Heaven for 40 minutes with no issues and nothing looking abnormal, not in nvidia debug mode of course. Here are the pictures I took of my second monitor with hwmonitor open at the 40 minute mark.
 


 
Only thing that stands out to me is that 11.808v low on the 12v rail but so far as I know that's within tolerances? So I'm a bit stumped.