Same as Fig. 7 but showing the influence of numerical parameters. Panels a, b: SFR does not really depend on the limitations on velocity and temperature of the gas and on the velocity of the massive stars in the sink particles. Panel c: influence of the shear on simulations at higher resolution. Panels d, e: star formation depends on the density threshold of the sink particles, giving a numerical incertitude factor of approximately two on the SFR.