  We present an experimental comparison of the efficiency of three General Game
Playing systems in their current versions: Regular Boardgames (RBG 1.0),
Ludii~0.3.0, and a Game Description Language (GDL) propnet. We show that in
general, RBG is currently the fastest GGP system. For example, for chess, we
demonstrate that RBG is about 37 times faster than Ludii, and Ludii is about 3
times slower than a GDL propnet. Referring to the recent comparison [An
Empirical Evaluation of Two General Game Systems: Ludii and RBG, CoG 2019], we
show evidences that the benchmark presented there contains a number of
significant flaws that lead to wrong conclusions.
