Howdy patten, we've made a lot of tests with every released production of the Citation X. It seems that since two releases of your model ago, we have experimented problems with the CDU and FG.
Starting the flight everything is okay, however when the flight takes time, lets say about +1 hour later, frames are okay but interframes became very high. Starting the flight interframe spacing time is 40 FPS 40, about 1 hour later interframes goes up for 600 ms while FPS standing on 40. Causing a strange nature lag every some seconds. Making unable to continue the flight.
We have tested on several FG versions. With and without your last two model releases and just the immediately previous one, which is not suffering such problem in any of the FG's release we tested.
How you doing ?