In this work, we introduce a new platform for frequency-multiplexed reservoir computing based on an optical cavity driven by pulses whose repetition period is matched to the cavity roundtrip time. The input symbols are encoded by modulating either the amplitude or the phase of the driving pulses. Our numerical results show that the proposed synchronously pulse-driven cavity operates in a weakly nonlinear regime under anomalous dispersion, while under normal dispersion it exhibits optical bistability with a high-peak-power upper-branch state. By isolating the key physical parameters, we quantify their individual contributions to information-processing performance. We further show that spectral symmetry breaking induced by third-order dispersion and Raman scattering almost doubles the information-processing capacity. Finally, we demonstrate that modulation-induced branch switching within the bistable regime limits stable reservoir operation.