How to Keep your Computer Running Cool by Eliminating Dust

Dust.  Any technician or computer savvy user has come across it, and probably has accidentally filled their lungs with the stuff trying to see what is even inside the computer they are servicing.  It cakes the blades of your fans and clings to heat sinks destroying their ability to function properly.  Dust on your fan blades impact their ability to move the air and can reduce their lifespan.  Dust in your intakes clogs the systems ability to pull fresh air to cool your components, and in the exhausts prevents the heat from being expelled.  On top of that, dust on your components reduces the heat transfer from the heat sinks to the air being used to cool the system.

Oh, and it’s really ugly.  Especially if you have a case that has a window and lighting inside, it just looks awful and maybe calls into question how good the system is or how much it is cared for.

Aesthetics aside, is there anything you can do to prevent this unsightly situation that is hazardous to your computer’s health?  Is regular dusting with a can of air the only way to keep your computer dust free?

When dust gathers in your computer, it reduces the ability to cool itself and has to reduce how hard it can work to protect itself.  The technical term for this is “throttling” where the processor is given less power thus restricting its performance and consequently, reducing the heat that it is producing.  The processor will continue to throttle down whenever it reaches the configured threshold. 

Annoying as it is, the throttling is a lifesaver when it is happening occasionally.   However, when your system is throttling on a regular basis, it puts undue wear on the components reducing their life span as they heat and cool in short periods of time.  Rapid Temperature flux is bad for your computer in a long-term situation.  A component heating up is just fine – but moving back and forth between hot and warm you subject it to small expansion and contraction reducing its lifespan.

A component that heats up and cools down then heats up again in very short time periods is going to fail much sooner than one that runs at a medium high heat all the time.  But let’s dispense with the description of why and get to the part where we show you how to avoid this.

Location

Before you can determine how to cool your system, you have to determine where your computer is going to be located.  Whenever possible, avoid placing a desktop computer on the carpet, especially carpet underneath a desk.  When this is unavoidable (as is frequently the case) you need to have a special set up if you want to reduce the dust damage to your system.  See Figure 2 for a description of how to do that.

Case Selection

If you are building your own system, you should consider where the system is going to be placed – remember that if you can avoid placing the system on the carpet, it is going to need much less maintenance.  Whenever possible, select a case that has easily removable air filters for your intakes, as this makes maintenance so much simpler. 

If you are buying a computer pre-built, try to find one that will function well in the given location that it is going to be located. 

Fan Direction and Air Flow

Now the tricky part – making sure that the air flow goes the right way.  Also, the quality of the fan is important as well, particularly the fan that cools the CPU.  As a professional, the brand of case fan that I recommend based off extensive testing, are Noctua branded fans, though sometimes the budget will prohibit it.  Just remember that a cheap fan will be louder and likely less reliable.  In the diagrams below, I have shown some scenarios of how you should configure your air flow in specific scenarios.

Different cases are used as examples, starting with a standard setup, then how to configure your system if it has to sit on carpet.  Figures 3 and 4 illustrate the most complex setup for

First, we have a standard system, set on a hard surface with airflow available.  In these systems you will almost always draw the air from the front and expel it out the rear, top or side of the case.  It’s important to make sure that your expelled air isn’t more powerful than your input air, or you will get dust drawn in through unfiltered holes in the case for cheaper cases.

Depending on how much of a load your system is under, you can get away with a much cheaper case here, and many retail purchased systems are configured to be placed on a hard surface with decent airflow.  Never place a computer inside a cabinet without airflow.

Image taken from product pags for the Core 1000

Now, for what is likely the most common cause of excess dust in a computer – being put on carpet under a desk.  The proper cooling solution for this is probably not what you think – you actually want to push the air down.

Figure 2:  Computer placed on carpet, under a desk

Images taken from product pages for the Fractal Focus G and the Masterbox Q500L

What’s happening here is you want to avoid the dust from the carpet at all costs.  Whenever you have a case that is on the carpet, its critical that your fans expel the air downwards.  Sounds completely counter-intuitive, but there is a very good reason.  With the fans pointing down, you create pressure that prevents the system from sucking up the dust from the carpet.  The worst thing you can do with a computer placed on carpet is draw air in from the bottom of the case. 

Dusty Environments

It’s important to remember that everyday dust and environmental dust such as rock dust, drywall dust and sawdust.  Rock and Saw dust are heavier and usually coarser than your everyday dust.  If you have a system that is in an absolutely excessively dusty environment, then it would be worth the investment to do a complete liquid cooling setup, but this is something that is beyond most experienced computer builders.  It’s a completely different skillset, and we’ll talk about that later.

Depending on how much load the system is going to have, you can simply go with heavy filtration and maintenance.  If your system is running intensive software, you would need a case with maximum filtration ability, or a closed system with liquid cooling.

If you need the system to be sturdy on top of everything and it doesn’t need to be super powerful for graphics processing, the recommendation I would give is to buy a sealed unit that is designed as a massive heat sink.  I’ve seen this used in systems that are built into mobile labs that are taken out on dirt roads into the oil field.  This setup relies on the environment having at least a small amount of airflow, so you may have to set up a fan nearby if it is in a confined space.  But for now, let’s show you what you can do to deal with dusty industrial environments.  You can see an example of such a system here.

Figure 3: High Airflow for dusty environment (on hard surface)

Image from the product page for the Fractal Focus G

Note that the intakes all have filters in them.  You can remove the filter from the top of the case if you are having issues with overheating to increase air expulsion.  In the second image, the processor has a sealed liquid cooler on it so all other air has to be expelled through the rear.

But what about if you have to put it in an excessively dusty environment, and still need full profile performance?  Well, in that case, you have to move to full liquid cooling. 

Liquid Cooling?

Liquid cooling has its benefits and its drawbacks.  The biggest benefit of liquid cooling is it reduces how quickly your system heats up.  This keeps your components from being damaged by rapidly fluxing temperatures, even if the processor throttles.  Because the liquid has a higher capacity for heat, it is also slower to cool down than air, and the liquid will keep the processor throttled for longer as the heat slowly lowers instead of rapidly. 

Another big bonus is that a liquid cooler is not impacted by dust on the components because it has direct contact with the component itself and the liquid is isolated from the dust.  However, dust will still impact liquid cooling on its exhaust, reducing the performance of the fans used to expel the heat absorbed from the system. 

There are a couple of significant drawbacks to liquid cooling however – the first being prohibitive cost if you aren’t building the watercooling loop yourself.  The case below costs $700.

The next drawback is that under a prolonged load, the system will gradually get hotter – and if it hits the heat threshold for throttling the processor, it will take much longer for the processor to cool enough to work at maximum capacity again. 

Figure 4: Custom Liquid Cooling

Image from the Singularity Wraith Mini-ITX Water Cooled case

For this setup, note the substantial temperature difference as you start to put a load on the system – as the water absorbs more heat, the ambient temperature of the lower portion of the case will rise, and this will continue until either the processor reaches a throttle point, or in an ideal case, the cooling capacity equals the amount of heat being produced and the temperature stays at its maximum point.

So, what is the best option for cooling your CPU?  For the processor itself, you want something like the  

Do you have a special scenario where keeping your computer cool or dust free seems impossible?  Give us a shout at cooling@plutomicro.com and the author will see what advice he can muster for you.