Use the reduced placemark file. This doubles rendering speed.
[marble] / packaging / debian / marble-maps.install
1 opt/marble/share/marble/data/maps/moon
2 opt/marble/share/marble/data/maps/earth/bluemarble
3 opt/marble/share/marble/data/maps/earth/citylights
4 opt/marble/share/marble/data/maps/earth/plain
5 opt/marble/share/marble/data/maps/earth/precip-dec
6 opt/marble/share/marble/data/maps/earth/precip-july
7 opt/marble/share/marble/data/maps/earth/schagen1689
8 opt/marble/share/marble/data/maps/earth/srtm
9 opt/marble/share/marble/data/maps/earth/temp-dec
10 opt/marble/share/marble/data/maps/earth/temp-july