Within the project funded by the Förderverein Mobile Arbeitsmaschinen e.V., the potential for increasing energy efficiency through the use of secondary-controlled rotary drives with constant pressure supply was investigated using the example of a hydraulic mineral fertiliser spreader. Different consumer loads during parallel operation of several hydraulic drives lead to power losses in resistance-controlled load-sensing hydraulic systems, which can in principle be avoided in displacement-controlled systems. To quantify the useful power and power losses, a test vehicle was set up on the basis of a hydraulic two-disc mineral fertiliser spreader and comparative measurements were carried out with both hydraulic architectures in typical application scenarios.