Shortening the thermal path between the semiconductor junction and the working liquid through direct-to-package microfluidic cooling leads to higher heat-load capacity. This study investigates which among the five states of cooling should be chosen based on maximum heat-load capacity, junction-to-ambient thermal resistance, coolant economy, marginal flow return, and resistance partitioning when all parameters are considered under the same constraint of maximum junction temperature. The five-state matrix consists of ambient convection, detached liquid heat sink, and direct-to-package microfluidic cooling with 0.10 mL/s, 0.15 mL/s, and 0.20 mL/s flows. From there, heat flux, conductance, power lift, resistance reduction factor, coolant economy ratio, resistance-corrected merit, resistance partitioning, preference index, and load-dependent choice criteria are calculated. The 0.20 mL/s state provides the strongest absolute performance with support for 41 W, approximately 641 W cm−2, 6.72 K W−1, and 17672 W m−2 K−1. When coolant economy is considered based on inventory inside the package, the 0.10 mL/s state becomes the optimal choice, reaching approximately 578 W cm−2 while consuming only 2 mL of coolant. It also gives the highest resistance-corrected merit value. The 0.15 mL/s state only adds 1 W with minimal reduction in thermal resistance. In contrast, the second flow increase to 0.20 mL/s offers more significant improvement. Partitioning of resistances indicates that 80 % to 82 % of total resistance comes from the effective convective/spreading term, prioritizing effective wetting area and flow rate over package stack thermal conductance. The decision boundary occurs at λ ≈ 0.486 which separates peak-performance regime and coolant-economy regime. The result shows that optimal flow choice must be determined by load conditions; lower flow for efficient steady-state operation, higher flow for peak thermal loads, and mid flow only for transitional cases.