Energy density is not the only metric for capacitors. In high pulse repetition rate modulators and other types of power conditioning systems, the reactive power (kVAR) is often the factor driving the physical size of capacitors. The specific power (kVAR/cm3) capability of a capacitor depends on many factors, including frequency, voltage, waveform, duty cycle, ambient temperature, and available cooling. The design of capacitors for high specific power requirements will be described. Designs using high-temperature polymer films as dielectrics and metallized electrodes will be compared to designs using common dielectrics such as polypropylene and both metallized and discrete foil electrodes.