Hello everyone,
 
I recently build my system with this power supply Corsair GS600 and a GTX 660 3GB SC (03G-P4-2666-KR), I noticed that under stress using my video card the PSU was like "suffering" making a really annoying sound like a buzzz, I would say it is coil whine. After a lot of research and some testing this is what I found out:
 
-There is a direct relation between the PSU and the GPU for the sound
-The PSU produces a lot of the annoying sound mainly while under stress generated by the GPU, when just surfing the web it will be quiet but if I try to watch a youtube video the sound will appear but not that intense.
-When I took out the GPU and played some less demanding games I had no issues at all with the PSU.
-There is a decent amount of people with the same issue, the GS version seems to have a lot this particular problem
-The designer of the GS version is Channel Well Technology and not Seasonic (not saying CTW is bad just to compare)
 
I don't know if someone here owns/owned a Corsair GS and had the same issue, I can't really say how good this Corsair GS version is but they doesn't seem to work properly with this kind of video cards and have some kind of incompatibility issue.