Computational comparison is presented between the scattered wave packet formalism and the non-Markovian time-dependent Schr枚dinger equation (TDSE). These two approaches have been developed to deal with open quantum systems. We employ these methods to study the dynamics of a Gaussian wave packet scattering from the Eckart barrier. It is shown that strongly oscillatory Green functions required in the integration of the non-Markovian TDSE significantly increase computational effort even for one-dimensional problems. Computational results indicate that the scattered wave packet formalism can achieve higher accuracy and can be several orders of magnitude faster than the integration of the non-Markovian TDSE.