I just sent an email to support, but just in case I can get any help there, I'm going to repost.
Everything was running smoothly and with no problems until today's patch. It caused me to go from a stable 60 fps to stuttering between 20-30 fps. I was able to sort of fix this by switching to fake fullscreen mode instead of real fullscreen mode, but this sadly broke my autohotkey script. It also prevents me from streaming the game properly using Steam In-Home streaming, which previously worked perfectly in fullscreen mode. There is definitely no hardware reason why I should be getting poor performance at all in this game, Here are some quick system specs.
Asus Maximus Hero VII Z97 Motherboard
i5-4690k @ 4.2ghz
GTX 780 3gb
16gb DDR3 1600 RAM at 8-8-8-27 1T