I think that it's possible that you have answered your own question.
Given that we hope that PSUs get more clever in power management, is it possible that your fancy new Corsair (a brand name that you'd avoid if you were English and of an age). Is it possible (yes) that it's looking at it's outputs and saying "that's a bit odd, there are four pins not doing anything, and I really really don't know what to do?"
P'raps leave your swap - in and rest on your laurels? After IIABDFI. (If it...).