DPC issues of unknown origin

[Doongle]

I recently got a new case (no other parts were changed) and now suddenly my PC is having issues with audio (caused by DPC according to numerous sources and latencymon)

I've done a fresh installation of my operating system and scanned my drives for corruption (none of them were) which leads me to believe the culprit is a damaged motherboard. I haven't found any other instances where this has occurred though so I want to make sure before I try RMAing my motherboard.

I have already optimised my power management.

http://imgur.com/a/E9ZCr
here are the latencymon results while playing overwatch for a bit

system specs:
Windows 10
i5-6600K (stock clock
Cryorig H7
G.Skill ripjaw V (16GB)
Asus Z170-AR
XFX RX 480 GTR
Seasonic S12D (silver, don't recall wattage, it's an older PSU)
Intel 530 series 120GB ssd (for OS)
Samsung 850 EVO 500GB (games)
old seagate HDD 500GB (random crap)
Focusrite Scarlett 2i2 (not the culprit, tested on another PC with no issues whatsoever, drivers are up to date)

popping occurs less when I plug straight into the headphone jack on the PC but the results seem to be similar

 

[Supahos]

Sounds like either a grounding or shorting issue. Make sure no wires have cuts in the insulation. And that all standoffs areny touching anything outside of the holes in the board. Extra standoffs in wrong spots and cause an issue

 

[Doongle]

I'll crack open my case when I get home, but do you think the issue could actually be my power supply if the cables have no issues? (it's a fairly old unit now, I just told myself "it's a seasonic, there's probably another culprit" lol)

also (just out of curiosity), how does grounding or shorting affect DPC? Seems like it'd be just a hardware thing