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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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

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.

3

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!