Managing power rails, including: a plurality of power rails, each power rail coupled to at least one power supply and configured to support a plurality of similarly-configured loads; and a power rail controller configured to merge and split the plurality of power rails based on total power consumption of the plurality of similarly-configured loads. The power rail management also determines the optimal power rail mode (merge/split) based on current load of each rail and adjusts the dynamic clock and voltage scaling policy, workload allocation on each core, and performance limit/throttling management according to the power rail mode.