The installation and use of cooling fans in PCs is pretty
straightforward once you understand the airflow layout and mechanical assembly.
You need to learn the necessary skills to make sure you are
setting up your fans to direct the air where it will do the most good, as well
as how to choose (and mount) the correct fan(s) for your situation.
Computer fans are manufactured in five distinct varieties: case fans,
expansion-slot fans, hard-drive coolers, CPU fans and external drive-bay fans.
With case fans, there are several physical sizes that are
measured in millimeters.
Another measurement the manufacturer will provide is the CFM
(Cubic Feet per Minute) the fan is rated for.
As a general rule, the smaller the fan in size and the
higher the CFM rating, the more noise it will create.
Before you purchase additional fans, open your case to see what
kind of fans can be added.
The fan size must match the size of the opening in the case
to be at peak efficiency.
You will need to establish you have expansion slots
available if you want to add an expansion slot-style fan.
It is crucial you establish a pathway for the air being
moved inside your case to follow.
As an example, having all the fans blowing air from the
outside of the case to the inside is not as efficient as having fans on the
front of the case blowing cool air in while the fans located in the back of the
case are sucking out hot air.
It is recommended the best practice is to position a case
fan in the front bottom of your case (bringing in cold air) and at least one
fan mounted midway up the rear of your case (expelling hot air).
If possible, use two fans in the back to expel the hot air
as a lot of it is being introduced by the CPU cooling fan.
The mounting of case fans is done by using four
course-thread screws usually provided with the fan.
These screws are self-tapping and will be inserted through
the hole in the case wall created for a case-fan screw, then screwed into the
case-fan body mounting hole.
Make sure you use all four screws to hold the fan securely.
The installation of an expansion slot fan can target
specific areas where heat is generated.
When mounting one of these fans, make sure the expansion slot
fan is not in direct competition with the fan mounted to a video card.
Having the expansion slot fan blowing directly into the
video card's fan, which is trying to blow out air, will defeat both of the
Hard-drive coolers usually mount to the circuit board side of the hard drive
and work to keep it cool.
Because of the location of most hard drives, there is very
little disturbance from the air that is released from the hard-drive cooler to
the airflow pattern mentioned earlier.
External drive bay fans can provide an enormous amount if
airflow, assuming there is an external drive bay open.