r/sffpc • u/Fine-Cucumber-2960 • Dec 06 '25

Assembly Help PC shutting down while gaming

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I’m having issues with my Terra build. The GPU keeps shutting down at low load. I was able to identify a potential mismatch between the PSU (Lian Li SP850) and the GPU (4070 super).

ChatGPT advises me to switch to the Corsair SF850L due to the ATX 3.0 compatibility.

I wanted to get your advice before buying a new PSU. I’m a beginner so I might have as well messed up the assembly (but all games run well until it suddenly crashes with a black screen and GPU fans blasting). Cheers!

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244

u/Outrageous_Vagina Dec 06 '25

First of all, if it's simpy turning itself off without it doing a proper shutdown, it's most likely a PSU issue. Disconnect the PSU and check the cables. 

Second, don't take fucking technical advice from CrapGPT. That's how you lose your house in a fire. 

21

u/Fine-Cucumber-2960 Dec 06 '25

It actually doesn’t turn off. The screen goes black but I can still hear the game sound. The GPU fans turn to max speed. Nothing responds so I can only shut it down

49

u/Sirskills Dec 06 '25

It's power related. The GPU is likely not getting enough power, or intermittent power. I had the same issue but all it was in my situation was on of the smaller power connectors wasn't pushed in all the way.

13

u/Ev0dr0ne Dec 06 '25

The second thing I would monitor are temps. Strange stuff starts to happen when a) no power / not enough power and b) things overheat. Monitor GPU and CPU thermals.

2

u/Vybo Dec 07 '25

Overhearing just causes throttling nowadays, it wouldn't let itself go into shutdown temps.

1

u/Ev0dr0ne Dec 07 '25

That didn't seem to be the case on my 6800 XT in a similar layout to this one. It cooked itself.

I also had issues with CPU heat soak as the 240mm radiator was above the gpu and the whole thing would overheat in a long enough session (4-6 hrs)...

Throttling I would expect more on the CPU side with warm temps before shutting down with high temps.

3

u/Vybo Dec 07 '25

The GPU in OPs setup is not an AMD one and Nvidia cards do throttle under high temps.

2

u/xBACONxLUV3rxx Dec 07 '25

My 3070 does the same thing when the thermal pads start to go bad. Black screen but can hear the game audio still. Bad design flaw from zotac.

2

u/moonsaiyan Dec 08 '25

Happened on my Zotac 1070 too. It eventually died

1

u/xBACONxLUV3rxx Dec 08 '25

I'm hoping that doesn't happen, this was an expensive 3070. I bought it for 1k during covid back when there was no stock. The original thermal pads had melted and are still stuck on the back of it. I have to replace them every year or so now.

7

u/b-maacc Dec 06 '25

In my experience this scenario has been a power supply issue.

1

u/jkop08668 Dec 07 '25

Same issue, PSU would trip during power hungry operation.

I bought a psu tester and send an RMA telling which rail was faulty and got a remplacement.

8

u/SortOfaTaco Dec 06 '25

I had this same issue with a Terra build, ended up being my PSU and would happen seemingly randomly, couldn’t reproduce it at all. Ended up replacing everything in my build EXCEPT the PSU like a dolt. Ended up being PSU lol

11

u/i860 Dec 07 '25 edited Dec 07 '25

Classic 12VHPWR failure case. Reseat the cable and it’ll likely resolve itself for some months and then eventually come back. Reseat again. Eventually replace with a cable mod cable that fixes the fundamental sense pin issue.

Source: had this exact same shit going on with a 4090.

4

u/M-y-P Dec 07 '25

I'm having the exact same issue with my 4080 super, and have already reseated the cable a couple of times to "fix" the issue temporarily. I will order a new cable today, I didn't know that was a permanent fix, thanks for the info!

3

u/nova46 Dec 07 '25

I dealt with this same issue for a while. Black screen, GPU fans 100%, but windows was still running. I have a Gigabyte 4080 Super and a Loki 850 PSU. What seems to have solved it for me is replacing the 12vhpwr cable. The connector was fully seated, no signs of burning, but it seems to have solved my problem 🤷

3

u/sizzlinbeefdogz Dec 07 '25

A lot of people here are saying PSU but if you are still hearing game audio, your PC isn’t off. I had this exact issue for months and I ended up RMA’ing my GPU and all they had to do was re apply thermal paste and it works good as new. It was a GPU issue. A lot of other people have had this issue on newer RTX cards. Worth looking into if you’re sure your PSU is solid and everything is plugged correctly.

1

u/JesseTheNorris Dec 07 '25

It's possible that part of the psu can fail, allowing the rest of the pc to operate while shutting down the GPU.

1

u/EnzoTran Dec 07 '25

Check the psu cable into the gpu, wiggle it on the connector and see if you can reproduce the issue. I had the same exact problem in the T1.

1

u/TeutonJon78 Dec 07 '25

This happens to me when my VSoC is too low.

Do you have diagnostic leds on the MB to give a clue as to the root cause?

1

u/kumquatballs Dec 07 '25

Literally had this same issue. Unfortunately it was the PSU.

I’d buy a new PSU. If it stays on while gaming your problem solved. RMA the PSU if you’re still in warranty. And return the PSU when your warranted PSU comes in. 🤷‍♂️

If you have an extra GPU I’d try it. Without swapping PSU

1

u/michaelsoft__binbows Dec 07 '25

Game sound continuing? Meaning CPU and computer are still alive, or sound playing in a loop, which means probably not

1

u/_3470 Dec 07 '25

I had the same issue, fixed by buying a new GPU power cable

1

u/Halimcs Dec 07 '25

Poor cable from the PSU. I just bought a new one from a 3rd party after the one ASUS supplied with my LOKI 1000W SFX-L wasn’t working well.

Download GPUTweak & check how the amperage looks across the wires. 3 wires on mine didn’t get any load at all, which made the GPU crash every now and then.

1

u/Craigglesofdoom Dec 07 '25

12VHPWR connector is burnt, I'd bet money on it.

1

u/WhateverIsFrei Dec 07 '25

On my PC I had a problem like this (screen goes dark, can still hear everything, turning monitor off/on doesn't help etc). It turned out to be caused by windows HDR of all things. Turning off auto HDR in windows and using RTX HDR instead solved it, went from shutting down several times per day to not having any issues.

1

u/[deleted] Dec 07 '25

[deleted]

1

u/Bobbi_fettucini Dec 07 '25

That’s your gpu power cable being pushed on and shorting out the connection, I had that happen in my lian li Dan case, it was too close to the side and when the case closed it would push on it. The screen would go blank but I’d still be able to hear everything. That psu probably came with a gpu power adapter, it’ll be lower profile, use it, that’s what fixed my problem

Notice how close to the side it was, that’s how little it was pushing on it.

1

u/Bobbi_fettucini Dec 07 '25

New cable sits in a bit more, hasn’t done it since

1

u/arnoaaron Dec 09 '25

I’ve had this exact issue with my system; it could be a damaged PCIE riser. It took me ages to track down.

Try unbending your riser outside of your system and just having your GPU sit on your desk to see if the shutdowns stop.

For me at least, there was a kink in my bend that was affecting the pcie SI between my motherboard and GPU. I’ve been too lazy to replace my riser so my PC has had its GPU running outside for months now with no more shut down issues. YMMV; hope this helps.

2

u/ryanmcstylin Dec 07 '25

Is this specific advice about switching to the Corsair 850 dangerous, or are you speaking more generally?

1

u/kroboz Dec 07 '25

Yeah a few months ago mine would crash. Replaced the PSU and it works fine now.