We propose a novel technique to study composite reliability and performance (Performability) measures of hypercube systems using Generalized Stochastic Petri Nets (GSPNs).This technique essentially consists of the following : (i) a GSPN reliability model; (ii) a GSPN performance model; and (iii) a way of combining the results from these two models. Models and performability results for an iPSC/2 hypercube system under the workload of concurrent matrix multiplication algorithm are presented