According to embodiments of the disclosed subject matter in this application, a power management system with multiple voltage regulator (“VRs”) may be used to supply power to cores in a many-core processor. Each VR may supply power to a core or a part of a core. Different VRs may provide multiple voltages to a core/part in the many-core processor. The value of the output voltage of a VR may be modulated under the direction of the core/part to which the voltage regulator supplies power. In one embodiment, the multiple VRs may be integrated with cores in a single die. In another embodiment, the power management system with multiple VRs may be on a die (“the VR die”) separate from the die of the many-core processor. The VR die may be included in the same package as the many-core processor die.