This study investigates the design and thermal performance of straight microchannel heat sinks featuring sidewall fins, using the Fluent module in Ansys Workbench. The performance of these heat sinks is evaluated using the average Nusselt number and required pumping power. Results indicate that the incorporation of square-shaped fins enhances thermal performance but increases pressure drop. Enlarging the pin fin size significantly enhances thermal efficiency, yielding a 150% improvement in the Nusselt number, yet requiring higher pumping power. Reducing the distance between fins also enhances thermal performance, resulting in a 46% Nusselt number increase, but demanding more pumping power. Similarly, Reducing the channel dimensions enhances thermal performance by 51%, as measured by the Nusselt number, but necessitates increased pumping power. In summary, various design changes were investigated to understand their impact on heat sink performance, revealing trade-offs between enhanced cooling efficiency and increased pumping power requirements.