Air cooling is the basic and most common cooling method in computer systems. This method uses one or more fans to remove heat from the CPU, graphics card and other components. The fans draw cool air into the system and push warm air out. Air cooling is affordable, effective for most common computers, and easy to install and maintain. However, it can be less effective in extremely powerful or overclocked systems (targeted increases in operating frequency) and cause higher noise levels, especially at higher fan speeds.