Accurate models of lubricant films are necessary to predict the performance of bearings under complex operating conditions. This investigation compares load predictions of the Reynolds equation and bulk flow model to that predicted by a three dimensional pseudo-spectral technique which incorporates thermal and inertial effects. Four different operating regimes along with their associated dimensionless parameters are identified. Three of these regimes are discussed, namely: laminar isothermal, turbulent isothermal, and turbulent thermal. The results provide insight into the conditions under which the Reynolds equation and bulk flow model are in good correlation with the pseudo-spectral technique.