Final answer:
A retail-boxed CPU generally includes a stock fan which is designed to provide adequate cooling for the processor under normal usage conditions. Users who require better performance or quieter operation may opt for aftermarket cooling solutions.
Step-by-step explanation:
A retail-boxed CPU usually comes with a stock fan. This fan is typically provided by the manufacturer and is designed to meet the minimum cooling requirements for the CPU under normal operating conditions. Different CPUs come with different cooling solutions, but a retail CPU will almost always have a cooling fan included, so users don't need to purchase a separate cooling system unless they are looking for enhanced performance or quieter operation, often sought by gamers or users who heavily utilize CPU resources.