Premiere Pro playback choppy ONLY in full screen mode

I recently built a new editing PC for a feature shot on Sony 4K. Everything works fine until I expand to full screen (Ctrl ~). I have no other issues with playback aside from full screen. Also, I've exported and watched in full screen on multiple video players and it looks fine. I've also changed monitors and hdmi cords but the problem persists. All other programs and browsers play full screen fine, i.e. Youtube, Netflix, Windows Media Player. This seems to be a Premiere problem for sure. All updates are current and installed. I'm running Premiere Pro CC.

Does anyone have a solution??

My system:

Ryzen 2700x

Asus x470 pro

PowerColor Vega 64

32GB Gskill RAM

850W PSU

LG 27" 4K montior

2TB pcie ssd (media)

500GB pcie ssd (OS, programs)

1TB pcie ssd (scratch)