The GPU External Power Supply is a custom-built power delivery system designed to provide precise voltage regulation and high current control, replacing the voltage regulation module for high-performance graphics cards. The system is intended to be directly soldered to the core and memory voltage rails of a GPU, allowing for expanded and fine tuned power delivery; particularly useful in extreme overclocking scenarios where onboard VRMs may be insufficient. Powered by a standard 12V desktop computer PSU, the system uses multiple DC-DC converters to step down voltage while amplifying current to meet GPU demands. At the heart of the system is the TPS536C7B1 PWM controller, which orchestrates 12 smart power stages (AOZ5276QI) to deliver stable, high-current output. Communication is managed via I²C using an STM32 microcontroller, which facilitates onboard control via system buttons and the user interface, while also enabling real-time voltage and current monitoring and external control from a host PC. A key accomplishment was the successful design of two fully functional 6-layer PCBs, achieving configurable synchronized output across all 12 power stages under load. Major challenges included establishing reliable I²C communication between the onboard VRM and microcontroller, both fully integrated on the custom PCB, and debugging the first prototype for shorts to ground, parasitic capacitance, and incorrect component placements. Planned future improvements include increasing the number of power stages by adopting a different VRM controller, adding GUI functionality for reading status registers, and discharge resistors for bypass capacitors to improve power-down behavior.