Almost Any Activity Causes Undiagnosed Static

This is driving me right up the fucking wall.

I have a sound card and on board sound but no matter what port I use (be it the headphone jack on the mobo, back of the sound card or the front panel sound which is hooked up to the sound card) the annoying static is inescapable.

The problem is ten times as bad when I'm listening through my sound card, a buzzing, crackling noise is produced through one side of the headphones constantly, changing pitch depending on the operations being performed at any given moment. When I'm listening through the on-board audio there is no constant buzzing but I will get strange interference noises only when something is loading or I am moving my mouse. These problems occur regardless of whether the volume is on or not.

I've tried plenty of things in an effort to straighten out this situation before posting here but nothing seems to help. Possible solutions I have already tried include, but are not limited to:

Buying a sound card in the first place. (Trying to solve the on-board static issue)

Buying and hooking up a new power supply (different brand with more modularity) in multiple different cable management configurations.

Tested using multiple pairs of headphones and speakers through each output device. (They all work perfectly when playing through sources other than my computer)

I've ordered a car audio ground loop isolator on ebay and am eagerly waiting its arrival.

If you have even the most far-fetched, ludicrous, hair-brained clue as to what might help I will try it. I am at my wit's end.

EDIT: Somehow forgot to mention the parts which I believe are giving me trouble. Since I've eliminated most variables I can think of it is either my a) MSI Z77A-GD65 motherboard or b) Corsair 550D case.