Effect of primordial mass segregation for masses of 5 × 10³M_⊙ (upper panels) and 5 × 10⁴M_⊙ (lower panels). The plots on the left are unsegregated, the ones on the right segregated. The strong dependence of the re-virialization time on the cluster mass is obvious, but also the more destructive impact of stellar evolution on segregated clusters can be seen over the whole mass range.