Energetically, the rigid-molecule force field CSP results are mixed. A main assumption of CSP is that observed crystal structures will correspond to low energy structures; a perfect prediction corresponds to the known structures matching the global minimum (rank = 1) structure, or the lowest set of structures for polymorphic molecules. We observe excellent rankings for several of the EMs (ABT, HBT, HNB, MNT, TATB and the β and ϵ polymorphs of HMX, which adopt the lower energy chair conformer). However, several of the matches to known crystal structures are energetically ranked poorly at the force field level, which we attribute to the rigid-molecule approximation more than the quality of the intermolecular force field itself.