Question weird sound coming from my psu.


Nov 16, 2019
Hello everyone! So I recently built a new pc by myself, the first one I've built too. I've had it since about August. It has been performing wonderfully with no problems at all, until today when I was trying to connect a USB peripheral when I noticed there was a high-frequency noise coming from my PSU. It is very silent I can only hear it when I put my head next to the PSU. I've had this problem in the past with my old pc, which I bought already built, but it had a crappy Chinese PSU. But the noise was coming from it when the computer was turned on, but with my current pc, the noise is coming when the computer is turned off. I have a Corsair TX-M Series 750W PSU. I was already researching about it on the internet, but I found only that the problem was because the PSU was not 80+ certified, but mine is 80+ gold. Which means it should be good quality, right? Anyway, I will specify all of the stuff, that could affect it, So the first thing is that the pc has already turned off 3 times because of a power outage, the first 2 times it was a brownout, unfortunately, the first brownout happened and then I turned it on to check if everything was alright and then a few minutes later it happened again. And the third time was recently when the power disappeared due to a snow storm. I've been trying to get an ups, but currently, I just don't have the money. The second thing is that I have a led strip in the pc which is on top of a PSU shroud. And then the final thing which I think would affect it is that I have a feature on my motherboard, when the pc is turned off it still supplies power to the USB ports, I've been trying to turn the feature off, but I haven't found an option, so in the meantime, I just use a USB hub with a switch, because when I turn off the pc my keyboard and mouse are still lighting up.
80+ Gold indicates it has little wastage at different loads, it's not a direct indicator of build quality.
High pitched noise is not surprising, only annoying when you are sensitive to it (I used to be, but I'm not getting any younger). It usually means that you have a component vibrating under a current load. This can also be found in higher quality elements, and is often a matter of chance. It's not an indicator of build nor component quality - just a matter of that specific component vibrating at a frequency you can hear, instead of at a higher pitch.
Please consider that an ATX system is ALWAYS under some kind of tension - otherwise a simple short on the motherboard wouldn't power everything on. The fact that USB and the switch on lead are both 5V and you hear the humming even when the computer is powered off may be a simple indication that the vibrating component is a 5V one.
The only way to shut it off then is to power the PSU itself off, either through the (optional) power switch at the back, or by connecting your computer (and screen while you're at it) to a power strip equipped with a switch. The latter is often easier to make accessible, and provides better power savings (a screen on standby eats up to 2-5W).
I wouldn't be otherwise concerned with it.