Power supplies are often
overlooked when trying to eliminate fan noise. An easy solution is to use a
quality power supply with 120mm fan. Larger fans generally result in a quieter
running power supply. Other power supplies incorporate thermal sensors that
regulates the fan to an appropriate speed. Fanless power supplies uses the power
supply chassis to dissipate heat. Good case ventilation is necessary to keep
fanless power supplies running in optimal operation temperatures. Also, with
power supplies, a good rule of thumb is "you get what you paid for." Higher
prices mean better engineered products that are not only more stable and
reliable, but also takes noise into consideration during the design process.
Quiet Power Supplies 
