I've been getting poor performance in all my games despite normal thermals for the past six months.

On HWInfo, the voltage is shown to be only ~10.8V on the 12V rail and ~4.5V on the 5V rail. I'm looking to test this manually with a multimeter and find out whether this is a cause of low performance.

I have a couple of questions about this:

  • Most video tutorials tell you to connect the multimeter to a 4-pin molex connector, but I don't have this connector on my PSU. However, I do have a smaller floppy drive power connector with similar red, yellow and black wires. Can I use this instead?

  • Do I need to unplug my motherboard, hard drive and other components while testing the PSU, or can I test it with all of them plugged in and with the computer on?

  • Considering that my issue is primarily low gaming performance, can the multimeter accurately detect voltage when the GPU is drawing power and the PSU is under high load?

Even if I can't trace the low-performance issue directly to the power supply, there is clearly some kind of problem with it — this is because it sometimes trips the breaker. This usually happens when the power comes back after a power cut. This never happens with any other device in my home.

  • If your system was under full voltage load, that would be a bad thing, it would be mean your PSU wasn't powerful enough for your system. It's very unlikely your performance problems are because of your PSU.
    – Ramhound
    Jul 9, 2017 at 13:59
  • It is very important to note that voltage values reported from motherboard sensors are usually garbage. They’re so inaccurate you might as well ignore them completely.
    – Daniel B
    Jul 9, 2017 at 14:10
  • @Ramhound I haven't been able to isolate it to any other thing. I have no idea what could be causing this issue. Also there is no explanation for why my PSU trips the breaker.
    – Vikram
    Jul 9, 2017 at 14:14
  • 1
    The threshold is + or - 5%. You are way under the limit you probably need a PSU with more watts. The floppy drive cable can be used for voltage testing.
    – cybernard
    Jul 9, 2017 at 16:36
  • 1
    "Can I test the voltage with the PSU still connected to the motherboard and with the computer on?" -- Yes. "Is that safe?" -- YMMV. I could do it without harming myself or the PC.
    – sawdust
    Jul 10, 2017 at 0:23


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