Hi, everybody A question about how Orbx manages its installed sceneries in FSX. When installing some sceneries ( it can be a region or an airport ) Orbx adds some lines in "dll.xml" file located in : C: \ Users \ Name \ AppData \ Roaming \ Microsoft \ FSX These lines refer to " Objectflow_xxx.dll " file , dedicated to the installed scenery , and which is in the folder named "scenery" of the scenery : (example for airport 2WA1, the file is called Objectflow_2WA1.dll and is located in X: \ FlightSim X \ Orbx \ FTX_NA \ FTX_AA_2WA1 \ Scenery ) What are the role or function of these dll files, which heavily penalize fps FSX by their successive additions in dll.xml ? I ask the question because after deletion of the lines concerning these Objectflow_xxx.dll in the file dll.xml , I see no difference in Orbx sceneries ( objects to their right place and all animations are running) but FSX FPS jump from 20 to 30 points or more ? ? ? Thank you for any information .