I'm new to graphics and all of that so forgive my lack of articulate info. I have an MSI B350, Ryzen 5, 16G Ram, and just moved from a GTX 1060 to 1080 Superclocked. I've done literally nothing between cards in relation to X-Plane and display settings, and could not get above 30 frames, and would run typically in about 23FPS. No performance tweaking worked. I thought I could max everything out with the 1080, I've heard stories and watched youtube til I'm blue in the face. Finally I changed my GeForce control panel to "Let the 3D app decide", and changed my X-Plane graphics to Visual Effects 3/4, Texture and Antialiasing full, World objects full, no Reflection, no shadows, no parked aircraft, no Vsync. That's a solid 45FPS standard screen, and 30 in VR. If I pull Visual Effects back, FPS increases each time. I've been able to get 98FPS just from those settings outside of VR, but I love the 30FPS VR and 45 Standard setup. Looks great. By the way, if I set Visual Effects to full, my 1080 chokes. It's goofy. My other resources don't even break a sweat and my 1080 sets at about 45% utilization on these settings.
I hope that helps.