After briefly reviewing the most widely used approximations to the SOC Hamiltonian in the literature, we presented an implementation of a new approach to the calculation of the 2e-SOC integrals which makes use of their Cholesky representation, which was recently proposed by some of us . This novel method allows for significant speed ups without loss of accuracy, and it can be applied to the true Breit-Pauli Hamiltonian, as well as to its approximations. The novel approach has been implemented in the CERES package .