Do the same with the rest of noisy fans.
This "air cooler " is connected to five volts and does not make noise .
fan in the power supply
Be careful , it makes sense ( or rather, the more sense ) if the unit does not control the fan speed .
Remove the power from the computer and open the case.
Fan was blowing in the air , but was deployed as airflow and cooling will decrease . A cold air outside will be more efficient cooling. But that's not the only reason. The higher the intake site is located in the computer the less it will collect dust. The idea is to create a ceiling fan pressure in the housing, then it will not be with all the cracks near the floor to collect dust. The seemingly obvious theory , in practice, has not been verified . So I can definitely say that it is. A year later, it will be possible to draw conclusions. But without additional ventilation upper part of the body may deteriorate overall cooling (more on this below).
+ Wire soldered to one of the red (5 volts). This block is at the level of the fan on/off , but it does not prevent to reduce its speed. Control is implemented using a transistor as a key for the ground wire , so when resoldering positive lead management to continue. Practical sense in this control is not much. What happens is : the computer is turned on and in about a minute turn the power supply fan and have not turned off before turning off the computer.
Reduce speed of the power supply fan is not desirable in the case of small or no headroom . That is the power supply of 450 watts, which gives the computer 150 W can be done more quietly without significant adverse effects , and if the computer consumes 430 watts, then think carefully your decision.
customizable way to reduce the fan speed
You can leave a power of 12 volts, but add in series resistance.
On the fans , if not all , then most of the power voltage and current might power . For example, on the fact that the power supply you can see this information : «DC 12V 0.18A», the fan mounted on the back wall (photo below ) also shows «DC 12V 0.18A», and on the fan side of the cover can be seen «DC 12V 0.25A », this large and has a little more power .
From these data one can calculate the resistance of the fan turned on Ohm's law to include such a chain in order to reduce power or four times , for example, half the resistance of the fan , then power will decrease by about 2.25 times . In general, a variable resistor and can be plugged in to change the speed of rotation ( picking up the desired resistance range for variable ), you can build a simple circuit , which, depending on the temperature will adjust speed. But it's relatively difficult , and my goal-to give practical information you can use to easily make necessary changes.