Abstract: The invention relates to a method for verifying the performance accuracy of an NC machine by comparing a desired circular path with the actual circular path describing the actual movement of the machine and used in an NC machine having at least two servo control loops each of which is provided with an axis actuator for guiding a carrier in accordance with a position reference signal describing the desired movement path, and a path measuring system to record and feed back the position of the carrier. In this case, the actual circular path R.sub.M is formed from the position signals (x.sub.M) supplied by the path measuring system (33, 43) and, preferably, each of the position signals (x.sub.M) measured by the path measuring system (33, 43) is compared with the associated position reference signal (w.sub.NC).