12 minutes ago, airpet said:I have a corsair RM750x (purchased in 2016) plugged into a Gigabyte Z490 Vision G with i7-10700K.
A lot of times, as soon as I turn on the switch on the power supply but not on the case, the UPS alerts me to a power surge. When I measure it using a tool, I see anywhere from 80-200W being drawn without the computer being turned on, albeit only for a second or two at most.
I had this similar behaviour with an X99 board but I attributed that to a failing board rather than the power supply.
Is this normal? I don't believe so but I still need a second opinion. I never saw this behaviour before but I neither had a UPS nor a power measurement tool then, so I don't know if this has been happening for a long time.
Time to RMA this power supply?
What you are seeing is what's called 'inrush current'. Basically, it's the energy needed to fill the capacitors, inductors, transformers, and other components up to full prior to them actually doing something. Almost any electronic device (all but the most basic devices, like toasters) will have an inrush current of some form or another. That's why some (high draw, normally) electronics spark when you plug them in; the spark is a sign of high inrush current. You don't see that spark with your PC because you have a physical switch, so the plug is already in when you allow the inrush current do, well, rush in.