Case fans are used to blow air around the inside of your PC case, cooling critical components like your processor and GPU. They can be configured as intake or exhaust fans, and the orientation has a significant effect on how well they perform.
When properly configured, a set of intake and exhaust fans will keep your CPU and GPU cool while minimizing noise by expelling heat from your computer without bringing fresh air in. For best results, make sure you choose fans with the correct size for your case and that they have a high CFM rating (Cubic Feet per Minute) to ensure good airflow.
Intake and Exhaust Fan Configuration
The most common configuration for case fans is to mount intake (intake) fans in the front of your case, and exhaust (exhaust) fans in the rear or top of your case. Front intake and rear exhaust fans provide a flow of cooler air that passes over critical components and dissipates the generated heat. Simultaneously, hot air is blown out of the case through the back or top vents.
A single front fan in your case is a poor choice because the cool air it draws in cannot be replaced by another source of fresh air and just sits there stagnant until it becomes hot enough to rise and escape through the case vents. For this reason, it is important to always have more intake than exhaust fans in a case. Case fans