We have tested the approximate non-perturbative second-order treatment of the dispersion energy on several small, representative systems for which Korona and Jeziorski performed detailed comparisons of highly accurate dispersion based on density-fitted CCSD density susceptibilities. We made the comparison with dispersion in CCD+ST(CCD) approximation of Williams and coworkers. Other models of the dispersion used in these studies are dispersion obtained from TDDFT based on asymptotically corrected PBE0 functional, and TDHF response functions . Finally, we also studied SAPT corrections E (20) disp and the sum of all corrections up to the second order in intramonomer correlation, which we will denote as E (55)