  We present results of fully non-linear calculations of decay of the inflaton
interacting with another scalar field X. Combining numerical results for
cosmologically interesting range of resonance parameter, q \leq 10^6, with
analytical estimates, we extrapolate them to larger q. We find that scattering
of X fluctuations off the Bose condensate is a very efficient mechanism
limiting growth of X fluctuations. For a single-component X, the resulting
variance, at large q, is much smaller than that obtained in the Hartree
approximation.
