Abstract: In multi-display systems, such as video walls, comprising a control computing system providing content to multiple display computing systems driving a plurality of displays, the refresh rates of the displays can drift over time. This drift can introduce display artifacts, which can make for an unpleasant viewing experience. To counteract display refresh drift, a control system periodically compares display refresh timestamps of the individual display systems to a reference display refresh timestamp of a reference display system. If the difference exceeds a threshold, the control system determines clock adjustment information that is sent to the display system exhibiting drift. The display system utilizes the clock adjustment information to adjust the frequency of a display system clock, which can be done by writing the clock adjustment information to registers that control the behavior of a phase-locked loop that generates the clock used by display refresh circuitry.