P3D would definitely be better performance. But its essentially same as FSX (32bit). It's not worth to waste money and time. I am currently flying in both FSX and X-plane and manually transfering some airports from FSX to X-plane. In X-plane, the free HD mesh v3 is something similar to UTX but much better performance pluse something area have UHD mesh for free.
FTX is bad for performance. I bought Australia region, at Brisbane and Canberra airport, the FPS is under 20.....I had all options on. Guess what, you will never get the screen shot quality on their website.
By the way, I am using GtX1070, 4.5G CPU and 24 G ram. Now I will give GEX+UTX a try. My platform is FSX steam with DX10 enabled. REX4 ASN