AmberTools consists of several independently developed packages that work well by themselves, and with Amber itself. The suite can also be used to carry out complete molecular dynamics simulations, with either explicit water or generalized Born solvent models.

The AmberTools suite is free of charge, and its components are mostly released under the GNU General Public License (GPL). A few components are included that are in the public domain or which have other, open-source, licenses. The sander program now has the LGPL license. AmberTools is distributed in source code format, and must be compiled in order to be used. You will need C, C++ and Fortran90 compilers

The Amber16 package builds on AmberTools16 by adding the pmemd program, which resembles the sander (molecular dynamics) code in AmberTools, but provides (much) better performance on multiple CPUs, and dramatic speed improvements on GPUs. Major new features include:

Semi-Isotropic Pressure Scaling (GPU)
Charmm VDW Force Switch (CPU, GPU)
Enhanced NMR Restraint support + R^6 averaging support (GPU)
Gaussian Accelerated Molecular Dynamics (CPU, GPU)
Support for external electric fields (CPU)
Expanded umbrella sampling support (GPU)
Constant pH supported with replica exchange along pH coordinate (GPU)
Support for gas phase MD (igb=6) (CPU, GPU)
Support and significant performance improvements for the latest Kepler, Maxwell and Pascal GPUs from NVIDIA.