Framerate in X-Plane depends on many factors. Strictly speaking, your hardware is more powerful than an i7 3770 with a GTX 1050. But to compare apples to apples, you have to run X-Plane in the same settings on both systems. Are you comparing with the same graphics, weather, scenery and aircraft settings? Also, it doesn’t make much sense to measure X-Plane against other gaming software.
Moreover, if you have been following the discussions in this and other X-Plane forums, you’ll detect the simmers have developed a general preference for Intel and nVidia hardware—performance wise. That is not to say AMD has inferior hardware, but at least with X-Plane for the time being, that’s the way it is.
Going back to the first paragraph, I believe your hardware can get you much better than 20 FPS if you have the abovementioned settings/conditions at medium or a bit higher. But if you try to max things out, I bet they can quickly push the FPS south of 20.