This research presents a computational analysis of thermal management heat sinks incorporating phase change materials (PCMs) to enhance thermal efficiency. The effectiveness of thermal dissipation systems using RT44, n-eicosane, and paraffin wax was evaluated under a thermal flux of 800 W/m2. The results indicate that n-eicosane offers the best thermal performance, with a maximum temperature reduction of approximately 5.2%. Additionally, the impact of fin geometry, with the fin volume fraction set at 9% of the total heat sink volume, was investigated by comparing circular, triangular, and hexagonal fins. Triangular fins demonstrated the most effective cooling, followed by circular fins, while hexagonal fins resulted in the highest base temperatures.