A full-wave finite-difference time-domain code is adopted to simulate a large reverberation chamber including stirrers, actual antennas, and losses. Maintaining the stirrer geometry unaltered, the chamber performance is analyzed by varying its volume. In particular, stirrer uncorrelated positions and field uniformity are analyzed for one and two stirrers. In the case of a chamber with only one stirrer, the number of uncorrelated positions depends on the chamber volume. It increases by reducing the volume. On the contrary, the field uniformity continues to gain benefits from a chamber enlargement. A chamber with two stirrers operating in a interleaved mode has already a very good performance which shows a weakly dependence on the volume vari...