The rise of mobile technologies and cloud computing has increased the importance of energy consumption. On-package voltage stacking, where current is recycled between multiple cores, is a potentially effective solution to this growing issue. Two converters, a load-to-load ladder buck converter and a busto-load isolated resonant converter, are particularly appropriate for on-package voltage stacking. A four core system composed of either converter topology is evaluated under several current mismatch scenarios in terms of transient and DC voltage drops, voltage ripple, settling time, and power efficiency. The load-toload buck converter exhibits higher power efficiency and lower transient voltage drops as compared to the bus-to-load resonant converter. The resonant converter is lower cost, smaller in area, and provides isolation.