evga 1600w is your best bet.  10 year warranty too.  quality cables, quality power cable.  all kinds of voltage protection.  Its not silent - but there is a reason I refuse to get server psu's for my garage....the high pitch noise is too much.  Sure If you have multiple s7 then getting atx will be expensive, but if you run one, invest in a 1600w, you can re-use it for literally anything after and its good quality.