A friend of mine who has been selling PCs mostly to industrial customers for many years long ago told me that twice a year he opens his customers’ computers and gives them a good cleaning with a vacuum cleaner. It prevents many problems, mostly due to overheating when dust builds up on top of computer chips.

I remembered this piece of advice when my wife’s computer started to sound more and more like there was a hairdryer inside. The CPU fan kept running at full speed, even when it was just sitting there with the Windows desktop, not just running any CPU-hungry applications. It hadn’t always been so.

What is it about computer fans and dust? As processors got faster, they consumed more and more power and consequently, produced more heat. Thus the need for fans, which draw in not only air for cooling, but also the dust that comes with it and which tends to build up. As the dust obstructs the airflow, the fan keeps having to work harder and the less effectively cooled parts get hotter, which can shorten their lifespan.

My wife’s machine is a Dell Dimension 3100C, a low-budget machine based on the Intel Celeron D 330. This CPU is a low-end version of the Pentium 4, whose power-guzzling technology has since been abandoned by Intel in favour of the more energy-efficient Centrino / Core architecture that was derived from the older Pentium III.

Even the lowly Celeron D 330 has a Thermal Design Power (TDP) of 73 W. To cope with this heat output, it has a massive heat sink through which a fan blows air from outside the chassis. When I opened the box I found that the metal grill in front of the air intake of the CPU fan was clogged with a 5 millimeter layer of dusty fluff.

After undoing two screws that hold down the heatsink cover I could flip the hinged heatsink by 90 degrees and remove it, allowing me full access to the inside of the fan, so I could blow air against the dust with a plastic straw from inside. I vacuumed the entire motherboard and both sides of the fan air intake, while brushing and blowing the dust loose. An old toothbrush and a plastic straw or a can of compressed air for blowing away dust can be helpful. Also, put a narrow plastic tip on the vacuum cleaner, for use in tight corners.

When all was done and I put the heatsink back, closed the box, reconnected the power cord and switched the computer on again, it ran nicely quiet – almost like new!

I definitely recommend vacuuming your PC at least once a year, more if you live in a dusty environment or if the fan blows a lot because you like to use CPU-intensive applications such as games.