Windows 11 desktop pc shuts down randomly and gpu fans start spinning really fast.

Everything you mention, is good signs as for the sound and the temp that would need to be monitored, i don't see a problem with it as you temp fall in line of what normal use is, but it still could be a sign of a malfunction which should be monitored loud fans and spinning is typically a sign the gpu is trying to cool itself, just monitor, 6 hours is a a long time with no issue the driver reinstall sound like it fixed it which is also a good sign. again monitor it the other thing is to look at is your CPU, might not be any issue with it but just keep close eye on it, GPU seem to be have a problem that not easy to identify, but everything you done so far is narrowing it down that its not a software issue but hardware.

Im glad to be able to give you some help, feel free to ask any question, and if you need some more help please let me know. If there is not anything you need assistance with more feel free to rate and mark this as helpful at the bottom of your screen, otherwise im here if you need me

Is this screenshot ok? I just reinstalled the GPU drivers (they were up to dated already) from GForce Xperience and selected clean installation, restarted the pc and took the screenshot, outside doing this and changing the display port in the GPU for another one I did nothing, not even before and I always let games decide the recommended graphics configuration.

I got this GPU not more than 3 months ago so is basically brand new, I ran a furmark test just now and this was the score at 2K, I ran this test after letting it run more than 10 minutes previously but in that one it didn't send the results, I clicked Benchmark this second time so the temperature was already high for this test.

This is a screenshot of the event viewer, the only error is that one in the system tab, the application tab doesn't have any error nor warning around the time the screen turned black, and idk how normal or not it is but I see one 8:35AM event on top of a 5:15PM event there.

Your issue seem to related to a failing and or malfunctioning GPU. The temps are a good sign that its not over heating. Have you try removing and reinstall the driver, maybe even update them, also try to reseat the GPU. Outside the GPU is there anything else you noticing, One piece of info you did mention is that its not happen just while gaming it happen also while browsing, so again im going back to the Failing/malfunctioning GPU. The RTX 4070TI is a great GPU and its powerful you shouldn't be having this issue at least not yet but this depend on when you got it. They also start going bad if you use them alot when doing high gaming. Im curious outside what i mention have you tried anything to try to fix it yourself. If you can provide a picture of you task manager with your GPU stats on it, i can see if i noticing anything

Also go into event viewer to see if you getting any errors, this will show if the computer is detecting anything

Hi, is not a BSOD the screen turns totally black instantly and while writing this it just happened again, I was playing a game for like 6 hours at 4K to test it and nothing happened, but after I closed it and opened the web browser the screen turned black again.. and I noticed that it was actually the GPU fans the ones making that loud noise, not the CPU fan, because I disconnected the DisplayPort cable from the GPU and the sound stopped immediately, I reconnected it and it was still silent but the screen never turned on again, the monitor shows that nothing is detected.

I can only start again the PC by pressing the shut down button on the PC case.

The strange thing is that the GPU temperature never goes even up to 60ºC in any game, most of the time never gets even to 50ºC, the GPU it's a RTX 4070 Ti, and the monitor it's an ASUS VG289.

HI my name is Tamir, Im a windows/ Microsoft user like you. I have read over your issue to get an understand of it. Your issue doesn't seem like an overheating problem based on the temp you are giving me as a normal GPU temp while doing high end work like gaming is 65 to 85°C (149° to 185°F) but it shouldn't exceed that. But the temp is also based on the manufacture. The fan spinning its also normal as its suppose to do that when in use. Other than shutting down and the fan spinning are you noticing anything else, is it BSOD. Now you issue can be related to overheating and overuse and the new GPU will fix it, but if you can share some info what your experiencing this will help.