Result: almost zero db!
Development server has four ide hdd and two unboxed power supply. also all pci card slots full. this means high energy consumption and high temperature. i modded it to an old i486 hardcase and drilled small holes for a stable air flow. also cpu cooled with two combined psu fan. most psu fans designed for humidity extraction. their noise almost unhearable.
Desktop pc is easy part of operation. first tried Xigmatek aio-s80dp water cooler. looks like really high technology for a personal pc but i got two issues with this. first, it works great and creates a waterfall sound effect. like an aquarium. second, it was not fit my hardcase. yes first issue is a cover for this reason.
i refunded it and purchased durin d982 model of same brand. it uses constant thermal oil with copper tunnels. this is same technology in new era notebooks.
whatever, currently im installed durin d982 and got 25~30C in 100% cpu usage. new personal record! Today, we defeated the noise.