Frame rate drop at Buenos Aires (saez)

Hi allI have a problem that I always had, but now I would like to know if there is any solution.I experince a dramatic drop in FPS in the area south west of Ezeiza Airport. Same thing happens with or without Addon scenery for the airport. To the north and east of the airport there are no problems. I wonder if there is some kind of bug with the textures. Its all contryside, so it should not be to "heavy". I have a good system and usually I have no FPS problems - except for this specific area.Any ideas to what it is or what to doComments/ideas very appreciatetthansk