It is generally known that dust makes computers slower, and that cleaning out the dust regularly can make your computer run better.

What I have not seen, is why this happens. From what I know dust doesn't stop electrons from getting from one side of the computer to the other. Does the dust only clog up the fans, making the computer hotter, thus making the computer slower? Or is there some other more mysterious force at work here?

4 Answers 4


Clogging up the fan is one side effect. It is also possible that dust can cause a short-circuit because it conducts electricity. Dust can also inhibit airflow, which prevents heat from being properly vented.


While a rare occurrence, dust can cause shorts. Mostly it will screw up your fans and coat heatsinks, which negatively affects heat dissipation.


And once the heat goes up your CPU may throttle down to compensate. At least mine seemed to...cleaned it out and over all temp went down and perceived performance went up...never measured clock speed...maybe next time.

  • I know CPUs do this now, but when did they start doing this? Older CPUs, they just plain over-heated, right? Jul 16, 2009 at 2:19
  • it was probably about the 2000 era...they used to just explode when they got too hot.
    – webjedi
    Jul 16, 2009 at 15:07
  • ...and before then they were designed to run with only passive/convective cooling.
    – user
    Mar 14, 2015 at 20:48

On more than one occasion I have "fixed" a computer that would not power on or wouldn't give any video output by simply vacuuming out all the dust. It can't be a heat issue when the computer is just turned on and doesn't do anything. I think that hair is probably the most likely culprit of the short-circuiting.

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