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.
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.