For comparison my former computer was getting good FPS even at detailed airports. It was intel based: CPU I7 4770K (OC'd to 4.3GHZ), 32GB DDR3 1600MHZ, GIGABYTE GTX 1070 8GB DDR5, Mainboard GIGABYTE GA-B85M-D3H micro atx. At the most detailed and complex payware airport: KJFK I was getting a reasonable framerate of about 24. My settings were high but not extreme. I had to turn of shadows though. This was with X-Plane 11.05 which was a lot more optimized than previous. At other airports I did not even have to turn of shadows to get a reasonable FPS. Sometimes it was even higher than 24 at freeware but payware quality airports like KBOS. So I don't see why you cannot get better FPS, with your hardware. The only thing is your triple monitors.