PSU making a humming sound?

[TheHotDog]

So while I was gaming, I heard a oscillating humming / *Wubbing* sound as my GPU increases in temperature.

I am leaning more towards the PSU making that sound more so than the GPU, but it's pretty damn difficult to distinguish from which one it's coming from...

Any ideas?

Edit: PSU is Supernova G2 750 W, sapphire r9 290 gpu

After further inspection, I feel like the sound is actually coming more so from the PSU.

Is this normal?

 

[akilleazy]

You could do what people water cooling systems do, use a paper clip on the motherboard pin (green wire to black I think but don't quote me on it)

That starts the power supply up without the motherboard and could help you figure out if its the PSU or not...
Its probably just a capacitor or maybe even the fan
Will wait for someone more knowledgeable than myself on the matter to comment though

 

[PurplePhoenix]

Do you have a reference r9 ? Could be the fan on that as the cards do get hot.

PSU has a 10 year warranty so if needed you can always RMA it.