VATSIM is a very popular online ATC network used around the World. It can be used with both main simulators, Prepar3D and X-Plane 11. Today, VATSIM developers stated something about bad FPS disconnect on X-Plane 11.
Laminar research, the developer of X-Plane 11, included feature in this simulator, that will slower the simulation down, if the FPS are at 20 or below. This feature is due to the flight dynamics, so the physics of the aircraft won’t be broken. Unfortunately, by that way the simulation takes 2 times longer and it is not very suitable for online network.
The VATSIM developer said, in the article here, that they will poll the users about FPS in next versions of Swift, xPilot, and xSquawkBox. If the FPS will be at 20 or below, the user will get disconnected by the client and forced to improve graphic settings of X-Plane, to get more FPS. If the user won’t do that, he won’t be able to connect back to he network.
VATSIM developers highly recommends using the 3JFps or something similar to it, to improve the FPS. You can get more information about this update here. Foru further information, stay tuned on FSNews.