Scenery "pops up"?

I've installed FS9 on my new, high-end system (i7920 o/cd to 3.8, 6gb RAM, GTX275 card, etc.) Everything flows smoothly and I couldn't be more pleased. However, something isn't quite right in my fs.cfg and I could use some help. The scenery relatively close to the aircraft continually pops up, or perhaps the better term is that you can see it refreshing itself as the textures and the ground is being updated. Again, this is close to the aircraft - maybe 2 or 3 miles or so at low altitude. Any suggestions on what to change in the .cfg to load more of the scenery at one time? Thanks.