You didn't mention if you are using 110 or 220V for your input.
Most server PSUs are designed to be ran at 220V, although they can operate at 110V with a reduced power rating.
This may be one of the reasons they are running so loud, as although they can operate at the lower input voltage, this comes at the cost of twice the current (amperage) and in some designs can put out more heat then the same wattage with a higher input voltage due to the internal design of the circuitry. Many HP server PSU will have two ratings, something like 1200 watts at 220-240V input, but only 900 watts with a 110V input for these reasons. Better check it out and get back to us.
BTW, I power several rigs with HP server PSU's, but run them all at 240V (US) input and they may spin up a bit at first, but they quickly quiet down and run no louder than a normal consumer grade PSU after a few minutes.
I'm in uk so my supply is 240v at the socket
Heres a video........
https://www.dropbox.com/s/8s4r3daleooz17y/scv_1516101577766-1.mp4?dl=0Wall reading meters arrived this morning and i cannot believe the readings
Socket One, 750w PSU (1 GPU, riser and mother board) - 210w
Socket Two, 1200w server psu(6 Gpus and 6 Risers) - 1005w
Socket Three, 1200w server psu (6 Gpus and 6 Risers) - 1260w
So this is really maxing out..... First thing i'll need to do is get one gpu and rise off from socket three and on to the 750w psu but I really need advice here as to how best quite this unit and get it running safely
This is dual mining eth and sia
https://snag.gy/8P3WZp.jpg