Rising requirements regarding throughput rates of modern extrusion processes have led to a high demand of high-speed single-screw extruders. However, whereas the throughput rate is directly correlated to screw speed for conventional extruders, this correlation decreases at higher screw speeds. As established design principles rely on this correlation, the calculation of throughput becomes imprecise for high-speed extrusion. There are approaches addressing this problem, by assuming a partial filling of the screw, but these need experimental calibration for certain model parameters. Current research at the Institut für Kunststofftechnik at the University of Stuttgart focuses on the influence of pellet characteristics as well as the screw and groove design in the feeding section. The objective is to built-up a more detailed knowledge on the single effects and implement this into throughput calculation models. For this, regression analysis is used to identify the different effects in regard to their size and relevance. Regression models for the total as well as the specific throughput are tested and their agreement with experimental data is evaluated. An approach with two separated screw speed ranges shows the most promising results. The application for different pellet shapes, e. g. recycled material, is not yet possible and has to be further investigated. In future works a fully integrated model should be developed, which implements the identified effects via their influence on bulk density and combines this with established models.