RAM management & scenery add-on

Hello,We use to download many add-on sceneries. A question is how these add-ons impact on RAM and FS2002 memory ?Let's take an example: I want to fly over Germany. Lets's suppose I've installed a scenery mesh divided in 5 BGL files covering Germany. First question: Does FS2002 download in memory all 5 BGL files or just one or two depending on the aircraft position ?I've installed a landclass europe file (this is just one but very big bgl file, 5 100 ko. Since I've installed landclass europe file, I've noticed that downloading time (when I launch a new fly) has doubled (my autogen slide is on "dense").Second question: Does FS2002 download all BGL file for europe whatever aircraft localisation ?Last question : What are the upper limits in memory use with FS ?Thank you