The Power Integrity problem for high speed systems is discussed in context of selection and placement of decoupling capacitors. Power Integrity is maintained by damping the cavity mode peaks at resonant frequencies using decoupling capacitors. This article focuses on damping cavity mode effects in power delivery networks by the particle swarm optimization technique. The s-parameter data of power plane geometry and capacitors are used for the accurate analysis including bulk capacitors and VRM, for a real world problem. The optimal capacitors and their locations on the board are found using the presented methodology, which can be used for similar power delivery networks in high speed systems. © 2013 IEEE Electromagnetic Compatibility.