  The results from hydrodynamical TREESPH simulations of galaxy clusters are
used to investigate the dependence of the final cluster X-ray properties upon
the numerical resolution and the assumed star formation models for the cooled
gas. When cold gas particles are allowed to convert into stars the final gas
profiles show a well defined core radius and the temperature profiles are
nearly flat. Final X-ray luminosities are found to be numerically stable, with
uncertainties of a factor 2.
