Motivation In industry, single screw extruders are frequently operated via flood feeding, that is, the material flows down from full material hopper by gravity providing a continuous material column over the screw channel and the extruder feeds in by gravitation as much as possible. Therefore, the output of the extruder is determined by the extruder screw speed. In case of flood feeding, the degree of filling is usually one, except for special cases of scrap or high-speed extrusion. Whereas co-rotating twin screw extruders are operated via starve feeding, where the material is metered into the extruder by a feeding device and the extruder screw is not fully filled with material. The output of the extruder is independent of the screw speed and determined by the feeder. Starve feeding for single screw extruders has not really been industrialized, although it has been successfully shown that it provides a wider processing window like improved mixing, reduced motor load or minimized wall-thickness variation and the investment for one starve feeding device is quite low. However, most of the investigations were carried out at a low output range. In addition, most of the studies was performed only for smoothed bore single-screw extruders. Therefore, the present work is focusing on high-output investigations of grooved barrel single screw extruders. Results The experimental studies confirms good extrusions stability also at industry-standard output ranges for grooved barrel single screw extruders. A reduction of axial pressure profile and motor load as known from experiments with smoothed bore single screw extruders could be also obtained for grooved barrel single screw extruders. Furthermore processing parameters like melt temperature, radial melt temperature profile, heat flow in the barrel or specific drive power consumption was determined as a function of the degree of filling.