Variation of r_M, N, that is the half-mass radius normalized to global half-mass-radius of each simulation, with stellar mass. The simulations considered, Sim 3 at 11 Gyr (black circles), Sim 6 at 7 Gyr (green triangles), and Sim 5 at 7 Gyr (orange squares), show a decreasing trend with mass. The fact that also the least relaxed simulated state (with n_rel = 2.5) shows mass segregation suggests that this process sets in efficiently after very few relaxation times.