The performance characteristics of the parallel pumped magnetostatic amplifier are experimentally determined.The gain bandwidth product and noise figure are measured as a function of pump power and comparedwith the usual parametric amplifier theory. Deviations occur which originate from a broadening of thesignal and idle magnetostatic modes. This linewidth broadening increases with pump power and is due topump saturation effects. When the usual theory for the gain bandwidth and noise figure is corrected, closeagreement is obtained with the experimental data.