Downward blowing CPU fans, also known as top-down or push-pull fans, are a type of cooling solution designed to sit on top of the CPU and blow air down onto the processor. These fans are often used in smaller computer cases where space is limited or in systems where a more compact cooling solution is desired.

One of the main advantages of downward blowing CPU fans is their small size and low profile. This makes them ideal for use in mini-ITX or other small form factor cases where there is limited space for cooling components. Downward blowing fans can also be a good choice for systems where a more streamlined look is desired, as they do not take up as much space as tower fans.

Another benefit of downward blowing CPU fans is their ability to provide direct cooling to the CPU. By blowing air directly onto the processor, these fans can help to keep the CPU cool even under heavy loads. Additionally, downward blowing fans can often be used in conjunction with other cooling solutions, such as heat sinks or liquid cooling systems, to provide additional cooling.

However, downward blowing CPU fans do have some limitations. One potential drawback is their relatively limited cooling capacity compared to tower fans or liquid cooling systems. Downward blowing fans may not be able to handle very high heat loads, especially in systems with overclocked processors. Additionally, the direction of airflow from downward blowing fans can sometimes cause dust to accumulate on the motherboard and other components, which may require more frequent cleaning.

 downward blowing CPU fans can be a good choice for systems where space is limited or a more compact cooling solution is desired. While they may not provide the same level of cooling as some other options, they can still be effective at keeping the CPU cool in many situations.