This paper introduces a step response based method to predict the eye diagram for high-speed signaling systems. The method is able to predict accurately the worst-case eye diagram, and is orders of magnitude faster than the method using SPICE simulation with input of random bits. The proposed method is applied to search optimal equalizer parameters for lower-power transmission-line signaling schemes. Simulation results show that the scheme with driver-side series capacitor achieves much better eye area, and signaling throughput than the conventional scheme with only resistive terminations.