I've been getting frequent black screens even after checking the cables and reseating the graphics card. I measured the PSU's 12V rail with a multimeter and saw it briefly fall to around 7V, then return to 12V. It also reportedly reached 14V once. The drops seem random rather than tied to heavy load, and the problem has become more frequent. Today the display signal did not return until I restarted the computer. The system still boots normally, but I'm concerned the PSU may be failing and could damage the GPU or other components. Should I stop using it and replace it?
4 Answers
A brief drop that low is well outside the normal ATX 12V tolerance and could explain the black screens. Even if it doesn’t immediately damage the GPU, a failing power supply can take other components with it, so I’d replace it as soon as possible rather than keep testing it.
7V would usually make the graphics card shut down rather than directly damage it, but an overvoltage event around 14V could potentially cause damage. Regardless of whether the readings are perfectly accurate, the combination of abnormal measurements and worsening black screens is enough reason to replace the power supply.
You could check the voltage while running a demanding game or GPU stress test, but random fluctuations are still a serious warning sign. Since the black screens are getting worse and the display eventually failed to recover, I’d treat the PSU as defective instead of waiting for the issue to become easier to reproduce.
A healthy 12V rail should stay within about 5% of its rated voltage, roughly 11.4–12.6V. Seeing 7V or 14V suggests a regulation or measurement problem. The protection circuitry may not always react quickly enough to a brief transient, so I wouldn’t continue using that PSU with the GPU connected.
It doesn’t seem related to load, since everything runs normally most of the time, but the drops are becoming more frequent. The PSU is an expensive 850-watt model, so I’ll replace it next week rather than risk the rest of the system.