A comparative study on two neutron noise solvers is presented. The first solver is the simulator CORE SIM which is based on neutron diffusion theory, while the second one makes use of a discrete ordinates method. For the comparison, a two-dimensional, heterogeneous critical system with a localized perturbation, is considered. The perturbation is defined as a fluctuation of the macroscopic neutron capture cross-section in one point of the system. Differences can be found between the two solvers because of the heterogeneities of the system and the perturbation.