Yeah, I added those programs after testing the game, had to work on that PC too so I couldn't keep it bare bones for long heh. Thanks for the suggestions. I ended up trying with a different graphics card I had (GTX 980TI) and I don't have issues now, however it still strikes me as strange that FFXIV is the only game that presented issues with the previous GTX 1080 card. I also tested with DX9 and that also solved the issue, but I wouldn't consider that a solution since a GTX 1080 is a DX12 capable graphics card; the fact that the game has to be played on DX9 feels terrible. Using the GTX 980TI with the i9 processor doesn't seem to cause problems, so I'm still at a loss on what it could've been.

I guess it'll remain a mystery, but even so you could consider the case closed. Thanks for the help.