[SOLVED] Hissing coming from power supply

[GoodPenguin]

When I use my computer with light loads everything is fine but when I start a heavy task on my desktop the power supply starts to hiss. From my quick research it sounds like it needs replacement but would like to know for sure from the tom's hardware community. I have already purchased a new power supply just in case I do need to replace it but can cancel the order if I don't need a new one.
I currently have a CORSAIR CX-M Series CX550M 550W 80 PLUS BRONZE and I ordered the 650W version to replace it.
Thanks

I should add my computer would be fine with a 550W but just decided to upgrade to 650W because the price wasn't that big of a difference and would be convenient for future upgrades.

 

[mangaman]

Sounds like coil whine. Try to take a popsicle stick and gently stop the PSU fan's from spinning. Open a program that is resource intensive and if the noise stops, its coil whine.

However, it could be other fans in your system too, such as GPU, CPU and case fans causing coil whine. Test those out too, if you still hear the hissing.