Disclosed are systems and methods for providing in-service testing using a redundant segment. A device (e.g., memory, filter, GPU) is implemented as multiple device segments. For example, a filter including 1024 taps may be implemented as sixteen smaller filter segments that include 64 taps each. A redundant segment that is of similar size to the device segments is used to provide in-service testing of the individual device segments. For example, the redundant segment is provided the same input as a device segment and the output of the redundant segment and the device segment are compared to determine whether the device segment is operating correctly. Multiplexers are used to cycle use of the redundant segment to provide in-service testing of each of the device segments. For example, the multiplexers can be configured into different modes to provide for testing of the various device segments.