The difference is that this approach relies on equilibrium statistical mechanics rather than molecular dynamics.
Thus, it is the application of the Metropolis Monte Carlo simulation to molecular systems.
It employs a Markov chain procedure in order to determine a new state for a system from a previous one.
An additional advantage is that some systems, such as the Ising model, lack a dynamical description and are only defined by an energy prescription; for these the Monte Carlo approach is the only one feasible.
A range of software packages have been developed specifically for the use of the Metropolis Monte Carlo method on molecular simulations.