What is the primary function of a power supply unit (PSU) in computer systems?

The primary function of a power supply unit (PSU) in computer systems is to convert alternating current (AC) from the electrical outlet into direct current (DC) that the computer components can use. Computer components, such as the motherboard, CPU, and hard drives, operate on low-voltage DC power, which is essential for their functionality. The PSU ensures that the correct voltage levels are supplied to each component, enabling the system to operate reliably and efficiently.

Other options presented do not accurately reflect the PSU's core role. While cooling components is crucial for maintaining optimal performance, it is the responsibility of fans and heat sinks rather than the PSU itself. Storing data temporarily during processing pertains to the function of RAM (Random Access Memory) and not a power supply unit. Similarly, enhancing internet connectivity relates to network interfaces or modems, again not involving the power supply's primary function.