This paper presents a brief description of the protein side chain packing problem (PSCPP) and a performance assessment, on this problem, of three state-of-the-art algorithms: SCWRL4, OPUS-Rota, and CIS-RR. In order to perform a fair comparison, the algorithms are evaluated on three data sets, two of them were previously proposed in the literature and a set of 723 protein structures proposed here. Experimental results show that the achieved accuracy when evaluating the side chain's first torsion angle (X1) is of approximately 86% and around 69% for the first and the second torsion angles (X1+2), for all methods. Although all the algorithms achieve similar accuracies, SCWRL4 requires on average, less computation effort than the others. We highlight relevant aspects that need to be considered in order to verify whether or not this 86% is a theoretical upper bound for the algorithms' performance and what might look as a promising direction to follow in case an improvement is possible.