My EVGA 650 G2 power supply has started making a very unsettling noise, the sound is a little difficult to describe; it sounds like a sort of ticking/clicking noise but more of an electrical sound like arcing. It's not a regular ticking, more erratic sounding. It so far only happens in certain games and is very intermittent, it happens most commonly playing shogun 2 on the campaign map. It only happens under load, specifically GPU load as I ran prime95 for cpu load and the noise didn't happen. It doesn't sound like any coil whine I've ever heard (and I've heard quite a lot in the past including my current gpu).
 
Things I've tried:
-Cardboard tube to listen for and isolate the noise from all components and it's definitely the psu
-Tried mounting PSU facing down instead of facing up (not sure why i thought this would help but it didn't)
 
-With ECO mode (which i normally have switched off) the fan does not spin at all and the noise still happens so I assume its not fan related
-Replaced my gtx 970 acx with gtx 770 acx; noise still happens
 
My system runs absolutely fine, I have not had any problems except for some TDR display driver crashes but there was a lot of other people experiencing the same with that particular game (warframe) so I guess it's probably unrelated.
I tried to record the noise but the mic on my phone doesn't pick it up very well. I could try again if that would be useful?
 
I'm worried about RMA'ing it because the problem is very intermittent, it so far only happens with certain games and things like valley benchmark don't cause the noise. I don't like the prospect of dismantling my system and shipping off the psu for RMA if there's a chance evga/ebuyer wont be able to reproduce it when testing.
 
Any advise much appreciated 
 

Both my Evga 1300 G2 & 850 B2 make that exact sound. I've owned the G2 for about a year now and it's still rock solid. The B2 was just bought recently and it's doing great on my benching rig so far.
 
It can't be heard over the fans so it's a non-issue for me.