High-performance communication interfaces in modern complex electronic systems bring new challenges for board-level manufacturing test. Various means of calibration and error-correction that are incorporated into high-speed protocols tend to hide manufacturing flaws thus making comprehensive testing be an extremely hard task. Links transmitting at gigabit rates are especially susceptible to so-called marginal defects. Marginal defect often escape detection by commonly used test methods as they manifest themselves only under certain conditions that may sporadically occur during device operation in the field. As a result, undetected marginal defects badly affect system stability and reduce its overall operating margin. In this paper, we present a novel embedded instrumentation toolbox intended for use in volume production environments to screen out outliers and marginal devices. The paper focuses on instruments for testing marginal defects on High-Speed Serial Links and DDR3/4 interfaces.