AX750 coil whine - Which part should I RMA?!

[ult]

I build this rig 2 days ago and one of the first things I noticed was the annoying whining noise the PSU made whilst under high load, I first noticed it whilst doing WEI and more so on benchmarks/games.

Before anyone suggests C1E/Speedstep disabled and Vsync off, tried it... did absolutely nothing for me.

I'm 100% the whining noise is coming from the PSU since I've took the PSU out of the case and had my ear up close to it. (I've seen many others have coil whining issues with Corsairs)

But here lies the other problem, upon switching the GPU(560ti) to onboard the whining stops, you'd think it was the GPU now right? wrong! it gets worse.. I swapped my Vertex 3 120gb for my old trusty 37gb WD raptor......
Noise gone! (with the 560 ti back in of course) so now I'm really damn confused what is causing the PSU to whine.

Am I just another unlucky one with a bad PSU? is it just a bad combination/build.

Thing is I've seen reports of people with the same problem RMAing EACH of what I've just listed (PSU/GPU/SSD) and still having the coil whining noise.

Anyone have any idea which part I should send back for RMA??

This video shows exactly what I'm experiencing right now with my PSU.
http://www.youtube.com/watch?v=C4d23F2jehQ

Specs here as I've not bothered to make a sig yet.
CPU
Intel Core i5-2500K Sandy Bridge 3.3GHz
MOBO
Asus P8Z68-V PRO Intel Z68 (Socket 1155) DDR3 Motherboard
RAM
G.SKILL Ripjaws X Series 8GB (2 x 4GB) 240-Pin DDR3 SDRAM DDR3 1600 (PC3 12800)
HARDDRIVE
OCZ Vertex 3 120gb
CASE
Antec Nine Hundred Black Steel ATX Mid Tower Computer Case
COOLER
COOLER MASTER Hyper 212 Plus
PSU
CORSAIR Professional Series Gold AX750 (CMPSU-750AX) 750W ATX12V v2.31
Card
MSI N560GTX-TI Twin Frozr II/OC GeForce GTX 560 Ti (Fermi) 1GB 256-bit GDDR5 PCI Express 2.0 x16

 

[JeffyB]

My original AX850 had an odd sound to it at idle that went away under load (opposite of your experience) sounded like a field of crickets at night. Took the unit back to the store and they swappped it for a new one which makes no noise. I'd rma the psu

 

[ult]

RMA'd to ocUK for testing, I'm just not entirely sure the fault will show on the build they use to test it, hopefully they will replicate my build for the test... can anyone confirm if they do this? my original post should explain why.

From my RMA email

2. Testing - All returned items are tested by trained Overclockers UK Technicians. Any item found to be not faulty will be subject to a £12.50 + all shipping costs including collection charges if applicable + VAT charge. This does not affect your statutory rights.

So as you can see, I'm a little worried now, if they do find it to be in perfect working order and I get it back and I'm stuck with the same problem, I'm just totally screwed.

Oh well, lets see what happens in the next few days.