How to : Keep your System Dust Free

No matter how clean the outside, the dust inside is what matters

Managing heat and airflow in a desktop PC is something that shouldn't need constant vigilance. As long as the fans are working fine, and intakes and outtakes are unobstructed, the all too crucial business of removing the heat generated by tiny squares of silicon is what modern case design is largely about.

That doesn't mean that periodic maintenance should be ignored however. The problem is those case fans aren't just sucking in air, they are also sucking in the usual assortment of crud that that accompanies air. No matter how clean you keep the surrounding area, there is an almost inevitable buildup of dust in places within your system, deposited as the air flows through the case.

Dust buildup has been a problem with PCs as long as they have been around. It is often an escalating problem - dust gets trapped in a spot, and as more air passes over it the buildup grows until it can get to the point where it directly affects system performance, thanks to reduced coding efficiency.

To understand just why this is bad, one needs to appreciate what system coding is actually trying to achieve. The whole point of having air flowing through the case is to remove the heat being generated by the various chips within. If there is no way of removing the generated heat then the chips will continue tn heat up until they are outside of their intended thermal envelope. At this point they either cease operating reliably or just shutdown thanks to internal protections against such a buildup.
 
The Good and Bad of Heat-sink Design

Heatsinks exist to assist in removing that heat. They effectively increase the surface area of the chips by drawing heat away from the chip and distributing it around metal fins. This much larger area can then be efficiently cooled by passing air across it, air that is then exhausted from the case and replaced by cooler air from intakes.

It all comes down to thermodynamics -  if the ambient temperature is the same as the heatsink surface then no heat will be removed, Similarly, if the heatsink doesn't have any means of getting rid of the heat, both it and the CPU will continue to warm up.

The problem is that because heatsinks are designed to maximize surface area, they consist of as many fins as possible. This means that the airgaps end up being quite tiny, and the smaller the gaps, the more likely it is that dust will build up within. When dust starts building up two things effectively happen - the coating of the metal fins reduces their ability to transfer heat and eventually the gaps themselves ran fill up with dust, severely reducing the effective surface area available for heat transfer.

The other common place where dust causes a problem is in the space between a fan and the heatsink itself. We've seen this many times with CPU coolers, especially ones designed to blow downwards over the underlying heatsink. This ends up with dust forming an effective blanket between the fan and the top of the heatsink, preventing air from ever reaching the fins. Because these CPU fans are usually controlled by the motherboard, which reads thermal information from the CPU itself, they speed up in an attempt to push more air through the heatsink, which has little to no effect thanks to the dust layer.

Not Just a CPU Problem

Even worse, good motherboard design takes advantage of this CPU airflow to cool the power circuitry around the CPU itself. So not only does the CPU lose a lot of its cooling, but these areas also suffer. This leads to stability issues and potential crashes. Despite the fact that the MOSFETs and VRMs that sit in this area have heatsinks themselves, these don't tend to be prone to dust buildup, as they don't have the fine fins and airgaps that are seen on CPU and GPU heatsinks.

If you run a discreet graphics card then this can also be hit with dust issues. A lot of modern designs for GPU cooling use air tunnels, with a plastic shroud helping to funnel air over the heatsink and push it out the rear of the case. These can, over time, also fill with dust, which can be an issue because the very nature of shrouded coolers mean that they often can't see the buildup. It tends not to be as much of an issue because the focused airflow seems to keep dust from building up. But if you start seeing graphical artifacts, particularly in system intensive games, then it may be down to dust buildup.

What can be done ?

Regardless of what precautions you put in place, some degree of dust build up is inevitable. A lot of modern cases try to minimize this through the inclusion of dust filters on the intake fans. If you do use such a case, then you can't ignore dust entirely. Periodically checking the filters is important to ensure that air is actually getting into your system - if they fill with dust then you end up reducing the overall cooling efficiency of your PC. This means that fans may spin faster, and the overall internal temperature of your system will rise.


Removing the filters and giving them a wash in warm soapy water should be enough to get them back to working order. Just remember to give them a rinse and let them dry completely before replacing them. The actual removal process will vary from case to case - we are starting to see a lot of models now that have easily removable filters, often accessible from the outside of the case, although some may require you to get inside and remove fans to get to them.

Don't forget the power supply intake either. A lot of cases will not only have filters over the front intake fans, but also ones on the base of the case covering the intake for the Power Supply. While you don't really need to worry about dust buildup inside the PSU itself (and you should never, ever pull a PSU apart to clean out any dust), a blocked intake will drastically reduce the PSU's ability to stay cool, especially in modern cases where it is effectively isolated from the rest of the case's airflow.

As of CPU fans, there are a few things you can do. The first thing is to turn your PC off and disconnect it from the mains; you don't want to be doing any of the following steps while electricity is pumping it. Ideally you want to remove your CPU cooler from your system (largely so you are actually removing the dust from the PC entirely). If you find that there is a layer of dust between the fan and the heatsink, then you'll want to get rid of that as a a first stage. If the fan is removable then take it off and peel away the dust layer. However if this is not possible then we find that loosening the dust with something that will easily reach between the fan blades, suck as a wooden skewer or even a thin pen, will help you get the bulk of the dust out.


Once this is done, then a can of compressed air is the best bet for removing the rest. These can be found at some hardware and electronics stores (a quick Google search will help locate the nearest outlet). You can also use a soft bristled brush to remove dust, but compressed air is better to get into all the small gaps between heatsink fins. Just remember that when you replace your CPU cooler you'll need to reapply thermal paste before mounting it.


Graphics cards can be a bit trickier to de-dust. Because a lot use shrouded designs, it is hard to even see if there is dust buildup (usually you will have to infer it from rising GPU temperature and/or graphics card crashes). The first thing to do is to take the graphics card out of your PC. Ideally you'll want to remove the shroud before trying to remove dust but this can be a bit daunting for some, and isn't something you should do if you aren't confident in being able to replace it - try looking online to see if there is a dissembly guide for your model of card.


If you can't remove the shroud then the compressed air trick should work, but you will need to be smart about it. Take a look at the graphics card and note where the fan is positioned. Some older cards will have the fan at the rear, pushing air across the whole card and out the rear. Newer ones may have the fan in the centre of the card, in which case the air being push in two directions - in this case you'll need to use the compressed air to remove dust in both directions.

You'll likely never completely purge your PC of dust, but if you follow the above procedures you can minimize the impact that it has on your PC's performance. While dust filters need regular cleaning, you shouldn't need to do the full heatsink clean any more than once a year, and often you can wait until you notice performance issues before bothering.

Not only does cleaning keep your PC in tip top shape, but it can save you money purely through not having to replace parts. If you do develop system crashes or graphical issues then it may not be a problem with your silicon, it could be something fixed with a can of compressed air, rather than new components.