I already have sent you an e-mail, my address is wojciech.wlw at the gmail, please check your box - maybe it went into a spam folder.
I have to agree and disagree at the same time. I have myself, same as you, speculated some time ago that the PSU might be contributing to the issue, based on the replacements presenting the same problem for many people, but the H100 I had was grinding on a Corsair HX 850W (powered off 230V) that produced a perfect 12,00 V (measured with volt meter). That's why I have previously speculated that perhaps a voltage noise (ripple) might be a factor in conjunction with the voltage. The extreme case was with a man from Poland also, who also had a Corsair PSU (AX 1200 I think) and he RMAed the H100 7 times, each time getting the same issue, and ended returning the unit for a refund.
Based on my statistics I do agree that the issue is more common among people with "12,3V PSUs" but it's not exclusive to that condition.
I can reassert that this isn't necessarily a voltage issue. My PSU is putting out a constant 12.288v. My H80 is making the aweful grinding noise... I built the voltage dropper, which dropped my H80 pump speed from about 2238rpm to around ~2000rpm. The grinding noise got *louder* after I used the voltage dropper. Maybe I didn't drop the voltage enough... I know some people have had success when the pump is around 1700-1800rpm (using a fan controller).
Either way, hopefully Corsair come out with a fix soon, and I can do my 5th (and final) RMA to resolve this problem!