had the same pc configuration, cpu, mobo, removed the graphics card recently and the computer runs off inbuild graphics. get static from both the onboard audio and xtrememusic card, pc on, OR OFF. Tried plugging pc and speakers in different outlets and still same thing. definitely not the audio cable. no interference from cables, have moved them around. no USB devices plugged in. disabled all wireless and Bluetooth signals around. i get the same noise even if the computer is off, sound goes way if i unplug the pc from the power. seems to be an electrical interference from the mobo or the psu. only thing different about the pc now is the graphics card has been removed, and I've changed the fan on the psu. i doubt it would be the fan as i get the sound even if the computer is off.