We study optimal power splitting-based simultaneous wireless information and power transfer (PS-SWIPT) for two communication systems wherein all receiving nodes are subject to a decoding cost. First, for a point-to-point (PtP) channel, the optimal achievable rate is obtained, and then, for a two-hop half-duplex (HD) decode-and-forward (DF) relay channel, the achievable data rate is maximized. Finally, performances of the PtP system and the relay channel with DF and amplify-and-forward (AF) relaying schemes are discussed where we observe performance superiority of the DF relay channel over AF relaying and the PtP channel for sufficiently less decoding cost at the relay than the destination.