As stated in the title my PC suddenly completely shuts down as if i would lose power. I am pretty sure that it is the Power supply but i wanted to ask if it even is possible for a CPU or GPU to just let the whole computer lose electricity before i buy a new PSU
The biggest question to ask here is when does it happen. I would try running something like Fur Mark (a free gpu stress test) which will help narrow down the possibilities somewhat.
If it does crash consistently when running furmark it's definitely a load dependent issue, and could point either to GPU or PSU. Another diagnostic tool to use during this test is CPU Z which will tell you temps and usages of everything in the system. Take note of temps in the 80°s - 90°s c, and watch if something is spiking to that temperature quickly and staying there (slowly building up to that point during a stress test is not unheard of).
If you're having trouble replicating the problem (and this is a good idea anyway) then do some sanity checks. Make absolutely sure there aren't any plugs hanging part of the way out, and that none of your fans are stopped or blocked. Another problem that can sometimes be difficult to diagnose (and that causes random shutdowns) can be a cable that is pinched tightly behind the motherboard. The metal points of solder behind your motherboard can puncture the insulation of cables that are incorrectly routed behind it and cause shorts which can cause any number of issues.
Another issue that can be difficult to diagnose, but that can also cause spontaneous shutdowns is CPU mounting pressure. Depending on the motherboard and cpu combo (some are more sensitive to this kind of issue than others, early gen ryzen in particular) the motherboard itself can actually flex and cause unexpected behaviour or damage if the cpu mounting screws are too tight. Try backing them off slightly and see if the issue persists.
Lastly try the computer on other power outlets / power strips. Many random shutdown issues aren't even the fault of the computer itself, but rather the result of a wiring issue or bad surge protector. Double check by using known good cables and outlets in other parts of the house.
It's a little bit of a long to do list, but all of these options stop short of buying parts. It is absolutely possible that you need a new power supply, and I've had to replace a few over the years myself. But I've also spent money that I later found out I didn't need to. Hopefully this saves you a few dollars and some frustration.
It is a new build CPU AMD Ryzen 9 7950X GPU AMD Radeon RX 7900 XT and a 850Watt seasonic PSU it should not be to much for the psu a can Game and do benchmarks without problem just if the PC runs like 1.5h it randomly shuts down
make sure all wires are secure and snuggly attached to everything. Including the rest/power button switches, PCIe devices, sata devices, etc.
double check temps before crash to see if theres any issues while idle or under load there.
check and possibly post your windows logs and event viewer logs to look for possible issues leading up to right before the power fail events.
do you have any overclocks applied? (Including xmp/amp) if so set your motherboard back to defaults and test again.
make sure BIOS firmware is up to date (might as well make sure all your other drivers are up to date as well).
try each ram dimm one at a time in both primary slots, this may help determine a dimm issue.
Borrow or using another power supply would be the best way to full confirm or deny the issue being a power supply failure. When a computer just instantly powers off like that its usually either a power failure or some kind of critical harware failure hitting a failsafe and shutting down. Normally this issue points to motherboard or psu issues in my experience.
I had a pc do that for no apparent reason, until I checked the power switch. The spring couldn't push the button fully out, because the plastic was misaligned somehow, so it would randomly turn off.
I had a similar problem once when I incorrectly wired my PSU to my GPU. I didn’t realize that if the GPU has two PSU inputs, it requires two separate lines rather than a single line split. Seems obvious, but I’m not very bright.
Anyway, running two separate lines to the GPU fixed the problem.
Once upon a time.. my second machine ever over a decade ago I forgot to use standoffs, this caused the system to short out but turn on for about 10 - 15 minutes before turning off, would have to turn it back on after resetting power supply. Real bone head move on my part.
I had an old pc behaving like this. It would just shut down whenever, randomly: 5 seconds after the first beep when the pc turns on, while windows was loading, after the login, while playing, while doing nothing, literally it could happen whenever. Tried everything i could, software wise but without any avail. I had some spare parts so I changed ram, psu, removed gpu, put new hard disk: nothing worked. Moral of the story? It was the motherboard. Changed only the motherboard and the pc works just fine… 🤷🏼♂️ so it could also be a problem with the motherboard. If you can, be more specific in saying when those shuts down happen or if you can reproduce them, it could help you a lot.
Ps it could be the RAM as well, try using one stick at once (if you have more than one stick) and check if it still happens(try another stick if it still happens until it does not anymore)
I had this happen recently as well. Could be the CMOS battery on your motherboard. It should be trivial to check if replacing it fixes the problem before you commit to buying a new PSU.
Have you monitored the temperature at all? If it shuts off after 1.5 hours of gaming, that sounds more of a heat issue than power. It sounds like maybe a lack of thermal paste.
Get something like CoreTemp and monitor your CPU temps while gaming.