Extremely low FPS, ESMS (Malmo, Sweden)

HiI have the old Aerosft Scandavian Airports 1 installed. These where originally done for FS2002 and 2004, I don't expect them to work well in FSX with regard to transparency and so on, but I am getting a big frame rate hit it when at ESMS that takes me down to 2 - 3 fps. Also, textures are missing off some objects. When I cycle the views (s) all sorts of strange things begin to happen. The tower view just shows me sea; and then spot views have planes up in the air or below the ground and so on.I tried turning down scenery display settings in FSX but they have little or no effect. There must be some other cause. I used these airports in FS2004 without any problem, and that was on a much older PC.My specs today are:Intel i7 2.8GHz8 GB RamnVidia GTX 460.With that hardware I should not be getting any problem with this airport.Can anyone suggest what might be the cause?