Comparison of results of vacancy diffusion simulation in a deformed aluminium crystal by the methods of classical molecular dynamics and temperature-accelerated dynamics is performed. The crystal is simulated at sufficiently high temperatures of 550, 600 and 650 K, so that diffusion could be studied within the framework of molecular dynamics. In the calculations we use a version of the method of temperature-accelerated dynamics with a modified potential of interatomic interactions, previously proposed by the authors and already tested on two-dimensional atomic systems with pair potentials. The present results show the applicability of this approach for simulating realistic three-dimensional systems with many-body potentials.