Capacitance is very important in High Speed I/O power integrity network design. There are different form of capacitors being used on the High Speed I/O Power Integrity Network to ensure the performance of the circuit. In this paper, the effectiveness of MIM capacitance and MOS capacitance is compared. MIM capacitance comes in bulk quantity but placed further away from the HSIO circuits. While MOS capacitance comes in considerably lower quantity but placed closer to the HSIO circuits. As such, there is a performance trade-off during the power integrity design considering the two different capacitances. While MOS capacitance is the preferred choice, the introduction of MIM capacitance has become an attractive option; as it offers much more capacitance at lower price. Can MOS capacitance be replaced by the MIM capacitance? The discussion will focus on PDN analysis to describe the change in behavior and the validation results to show the gap when MIM capacitance is completely removed.