Sorry for the late answer. In the upcomming 5.7 release a verbose mode will be added to Generate3D which helps to follow long executions. This revealed that using 1.4 diversity value around 60 conformers are generated in a considerable running time.
The recommended solution is to decrease required conformer count parameter (to 60-65 for the attached structure). When 5.7 release will be out the implemented verbose mode can be used to estimate a suitable conformer count parameter.
A brief introduction to Generate3D (usage and inner workings) can be found at https://docs.google.com/document/pub?id=1dgaNFWpBNqexlTRMmWF48II9qkL9e8ALdyFpoIlJfUY
A tracker topic where notifications on the major modification of this document can be found https://www.chemaxon.com/forum/ftopic8016.html
Outputs (generated conformers and verbose outputs) from the following runs (using a development version) are attached:
time cxcalc conformers -m 60 -d 1.4 -l 90000 single_ligand.sdf > confs60.sdf 2>confs60.verbose.txt
cxcalc conformers -m 70 -d 1.4 -l 90000 single_ligand.sdf > confs70.sdf 2>confs70.verbose.txt
If you have further questions please do not hesitate to ask them,