Method for operating a piston pump with a differential cylinder drive with at least two differential cylinders for driving at least two conveying pistons movable in conveying cylinders, wherein each conveying piston is driven via an associated differential cylinder of the differential cylinder drive , with a hydraulic circuit for controlling the differential cylinder drive and / or for driving the differential cylinder drive by applying hydraulic fluid, comprising the following cycling steps: - suctioning of goods to be conveyed using a first conveying cylinder by driving the associated differential cylinder and simultaneously ejecting the material to be conveyed by means of a second conveying cylinder by driving the associated differential cylinder , - pre-compression of the suctioned material by means of the first conveying cylinder by driving the associated differential cylinder and simultaneous ejection of the material by means of the second conveying cylinder by driving the associated differential cylinder , - ejecting the material by means of the first conveying cylinder by driving the associated differential cylinder and simultaneously suctioning of material to be conveyed by means of the second conveying cylinder by driving the associated differential cylinder , - ejecting the material by means of the first conveying cylinder by driving the associated differential cylinder and simultaneous pre-compression of the suctioned material by means of the second conveying cylinder by driving the associated differential cylinder , characterized in that the pre-compression is divided into at least two phases, wherein in a first phase the hydraulic switch effects the pre-compression of the suctioned-in material in the conveying cylinder with the hydraulic fluid in a first mass flow and a first pressure and in a second, subsequent phase, the hydraulic switch effects the pre-compression of the suctioned-in material in the conveying cylinder with a second conveying cylinder speed reduced relative to the first conveying cylinder speed by applying the associated differential cylinder with the hydraulic fluid in a second volume flow rate reduced relative to the first volume flow rate, and a second pressure higher with respect to the first pressure. - suctioning of goods to be conveyed using a first conveying cylinder by driving the associated differential cylinder and simultaneously ejecting the material to be conveyed by means of a second conveying cylinder by driving the associated differential cylinder , - pre-compression of the suctioned material by means of the first conveying cylinder by driving the associated differential cylinder and simultaneous ejection of the material by means of the second conveying cylinder by driving the associated differential cylinder , - ejecting the material by means of the first conveying cylinder by driving the associated differential cylinder and simultaneously suctioning of material to be conveyed by means of the second conveying cylinder by driving the associated differential cylinder , - ejecting the material by means of the first conveying cylinder by driving the associated differential cylinder and simultaneous pre-compression of the suctioned material by means of the second conveying cylinder by driving the associated differential cylinder , <EOS>