Full electrostatics calculations now transmit less data and take better advantage of large clusters of multiprocessors to allow efficient use of several hundred processors for large systems.
Multiple images of a subset of the system with a reduced nonbonded potential can be used to increase sampling and transition rates.
A dual topology method allows NAMD to calculate free energy changes resulting from chemical mutations, the removal of ligands, etc.
NAMD can load GROMACS ASCII topology (.top) and coordinate (.gro) files, allowing most GROMACS simulations to be run in NAMD. There are, however, several performance-enabling features of the GROMACS force field which NAMD does not (yet) take advantage of.