The detailed origin of the diffuse gamma-ray background is still unknown. However, the contribution of unresolved sources is expected to induce small-scale anisotropies in this emission, which may provide a way to identify and constrain the properties of its contributors. Recent studies have predicted the contributions to the angular power spectrum (APS) from extragalactic and galactic dark matter (DM) annihilation or decay. We have updated the APS measurement with the Fermi-LAT using ~ 45 months data, and use accurate predictions for DM anisotropies from state-of-the-art cosmological simulations as presented in Fornasa et al. (arXiv:1207.0502). The new Fermi-LAT APS measurements are then compared with their predictions to derive constraints on different DM candidates.