Culling is a bit more complex than simply range, although that explains it fairly well. If culling were correctly implemented, it would take into account your position and rotation and only display visible items. Any items
occluded by one another would be removed also. That is until you side step and then see them from behind a large boulder for instance.
From what I can see TGC are working on a new FPE setting to help with this, and including a pre-bake occlude into the bake system. Since real time code, so far, has only managed to run at the same speed with it, as without it, pre-calculating it makes sense. Making this a read option rather than having to calculate on the fly will certainly speed things up.
SPECS: Q6600 CPU. Nvidia 660GTX. 8 Gig Memory. Win 7.