A "24 pin power supply" for Dell computers typically refers to an adapter cable that allows a standard 24-pin ATX power supply to connect to Dell motherboards that use a proprietary 8-pin or 6-pin power connector. These adapters convert the standard power supply's output for compatibility with specific Dell models like the OptiPlex 3020/7020/9020 or Inspiron 3470, but users must ensure the adapter is compatible with their specific motherboard before installation, as some models are not supported.