Does it hurt to put a bunch of .dem files into the dem folder? For example, do I need to put Basemap_North_America_CGIAR_2006.06_081103.dem AND United States Premium 2006.06.dem into folder? Do I need both base map and file or will the United States Premium 2006.06.dem be enough?

I started with only USA_CGIAR_Premium_2006.06_090313.dem and then put this in my sys.txt file:
[map]
3d_buildings=1
3d_landmarks=1
3d_dem=1 ; 3D terrain
3d_dem_detail=3 ; detail of 3D terrain (0 = none, 1 = low, 2 = medium, 3 = high)

But it does not work. I have iGo Primo 9.6.13.405512. When I look in content while in the iGO Primo, I can see that the .dem file is recognized and active. Please let me know what I am doing wrong.