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A 24-pin power supply is a type of computer power supply using a 24-pin primary connector. Older power supplies came equipped with only a 20-pin primary connector. The extra four pins provide additional power to the computer’s motherboard, which in turn provides power to internal components.
A power supply converts voltage from power lines into lower levels of voltage for use by a computer’s internal components. These internal components have different voltage requirements, and a power supply must be able to accommodate this. Several different connectors are used to supply all parts of the computer with power.
The main or primary connector on standard types of power supplies plugs into a computer’s motherboard, which distributes power to components like the processor, memory, and expansion cards. This connector has separate wires which supply voltages of 3.3 volts, 5 volts, and 12 volts.
A 24-pin power supply adds an extra line each of 3.3 volts, 5 volts, and 12 volts, as well as an additional ground. These extra lines are used to satisfy the needs of newer technologies and more power-hungry peripherals. They also replace older 12 volt auxiliary connectors found on some 20-pin motherboards.
The 24-pin connector became standardized as part of a specification called Advanced Technology Extended (ATX) v2.0. ATX is a common form factor specification for desktop computers, and there are several different versions. Any power supply conforming to ATX version 2.0 or above should have a 24-pin connector.
A 24-pin power supply should work with older motherboards that only have a 20-pin connector. The first 20 pins on both types of connectors are the same, and the final four pins simply go unused if they aren’t connected to the motherboard. On some power supplies, the final four pins are part of a detachable connector.
On the other hand, using a 20-pin power supply on a newer motherboard designed for a 24-pin power supply may be possible but can create an unstable system. There are adapters that add the extra four pins, but these often do not function as well as a true 24-pin power supply. It is generally best to use a power supply designed to match the computer’s requirements.
Even on computers with a 24-pin power supply, additional connectors may be needed for components that require large amounts of power. Hard disks and optical drives usually need their own connectors. Graphics cards often draw power from both the motherboard and a separate connector.