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As it gets warmer this spring, your ambient room temperature goes up, too — at least if you have your furnace and AC set to reasonable levels — which means your computer has to work harder to get rid of the heat it produces, so the CPU doesn’t turn into a molten pile of goo.  I didn’t know just how stressed my computer was till it started beeping at me as I was getting ready for bed the other night.

I followed my ears to my computer, which was trying to tell me that it wasn’t happy.  The widget I run on my desktop said the CPU temperature was 70°C — a little on the warm side.  After killing everything that was running, it still was too warm, so I shut it down to worry about it the next day.

The next day after I started up the computer the CPU temperature widget read 48°C — still a bit on the warm side.  I popped open the case and noticed about a year’s worth of dust caked on the CPU cooler, not unlike the photo above.  I shut down the system again and blew out the case with my trusty can of air.  If I’d been thinking I would have done this outside.

After the dust cleared and I could breathe again, I restarted the computer.  The CPU temperature now hovered around 32°C.  Simply cleaning the dust off the CPU heat sink and from inside the case lowered the temperature by 16°C (29°F)!

The moral of this story is that dusting your computer now and again can make a huge difference in how cool it runs.  So be kind to your computer — after all, it’s letting you read Toolmonger right now, isn’t it?

Thanks, eurleif for the great CC-licensed photo!


21 Responses to A Friendly Reminder To Dust Your PC

  1. Jim German says:

    This is why I like my PC cases to have little washable air filters on the air inlets. Its super easy to just take it off and rinse it out everyonce in awhile.

  2. Joel says:

    Thanks for the reminder! I usually skip the (expensive) canned air and use my air compressor. One tip that I always tell people is to HOLD THE FANS STILL while you blow them off. It is quite easy to spin a fan faster than it was designed to spin + blow out the bearings! I learned this the hard way… the fans do sound really neat though when you get them really going.

    Oh – and do this outside or you’ll have a very mad wife!

  3. Chris says:

    I’ve always wondered why more computer makers don’t put the case under positive pressure and filter the single inlet, rather than putting it under negative pressure and allowing every nook and cranny in the faceplate to become a dust collector.

    Or they could focus on not using so much damn power in the first place. All that heat dissipation is a sign that your computer isn’t anywhere near as efficient as it could be. (‘Nother reason I like laptops, even though they’re more expensive.)


  4. ToolGuyd says:

    Chris, my guess is that manufacturers try to maximize airflow and heat dissipation at a minimal cost. Plus, most people wouldn’t bother cleaning the filter, and dust will make its way into the system anyways.

    In any case, Joel makes a great point about stopping the fan blades to prevent damage. I like to go over fan blades with a cotton swab first to remove the really dense dust first.

    NEVER Vacuum inside a computer – I’ve heard a few accounts of frying components w/ static electricity. I’m a bit skeptical don’t dare test things out with my own equipment.

    I also would be a bit hesitant to use air from a compressor unless I was absolutely sure it was dry. A basic moisture filter costs about $20. Unless you have one already, that $20 can buy several cleanings worth of canned air.

  5. Thad E Ginathom says:

    The photo is very similar to how I found the inside of my PC just a few weeks ago. The floppy drive was totally caked with dirt!

    I always vacuum-clean inside PCs.

    Back in office days I had a fancy one that was supposed to protect the equipment from static and the humans from laser-printer powder. Now I just use the household machine. It hasn’t caused me any problems …so far.

  6. System Services says:

    My two cents worth:

    1) The amount of curd drawn into the computer will be reduced if the case is not sitting or lying on the floor. Keep it above floor level. Put a phone book under it or some such. Do not let the case settle into that nicely padded carpet.

    2) Try not to place fan openings too close to walls (especially fabric covered cubicle walls), or other surfaces that might hold dust and release when disturbed. The fan acts like a vacuum cleaner. The surface of the wall (or desk) is disturbed and a bunch of crud rains down and is sucked into the case.

    3) Shut the PC off before cleaning or vacuuming near it.

    4) In an office environment, quarterly maintenance should do. Computers aren’t fishing licenses; they don’t all have to be cleaned on the same day.

    5) Temperature is not the only issue. I have seen ribbon cable connectors short (in the sense that signals got on to the wrong pins) due to dust on the cable. Strange things happen.

    6) When using a compressor, be SURE to reduce the output pressure. 10-20 psi is more than enough. At higher pressures, you may blow connectors loose, force air and crud where it does not belong, etc.

    7) Be sure your water filter is in good shape too, and that the hose is not blowing bits of itself or something worse into the computer.

  7. Mitch says:

    Ben, you didn’t go and add dirt from your garden to ‘sex’ up that picture, did you? 😉

    re: Keep it above floor level.
    Taking that to an extreme, my computer is on a shelf 4 feet above the floor. I’ve got filters on the intake fans and they have not needed cleaning in the 4 years it’s been running.

  8. @Mitch:

    No the photo’s from Flickr, I didn’t think about taking pictures until after I cleaned out the case. It’s pretty close to the amount of dust that was on my CPU heat sink though.

    I said my CPU cooler had accumulated about a years worth of dust — after thinking about it, I think its more like 6 months. I blame Greta our German Shepard, she kicks up tons of dust and dirt outside and carries it inside with her.

    Sad thing is that I specifically bought a case with a filter, but the filter is worse than useless because air can flow right around it. I think PC makers are worried that people wouldn’t clean the filters and soon the computers would get no airflow.

  9. Dano says:

    Mine looks something like that. I wish I had a regular vacuum. I just have a Roomba….You can buy filters at Home Depot. Thin black foam ones or the white paper ones. You add cheap fan grills to the other side of the case. Or just tape the filters in place if you don’t care about the looks.

  10. Mitch says:

    re: Greta
    oh sure, the immediate response: blame the dog! 😉 I have two large Malamutes and one medium Husky. Greta’s got nothing on them in terms of fur and they bring in 3x’s the dirt and dust that she does. Having the computer 4-5 feet off the floor cuts the dust intake a thousand fold (I pulled that number out of my ass)

    Since I’m feeling a little holier than thou, I decided I better check my computer’s case fan filters and the internal contents. Just in case. oops. The front case fan filters do need to be cleaned. Thanks for the reminder. The internals are pristine though 🙂 Even with the computer waaay off the floor, I guess I should be cleaning the filters every 6-12 months. But since they’re case fan filters, I can simply vacuum them without worrying about whether the static story is true or not.

    re: “I think PC makers are worried that people wouldn’t clean the filters and soon the computers would get no airflow.”
    ?? But if the makers leave off the filters, then the CPU’s get crudded up and then they get no airflow. People are hosed either way, aren’t they?

  11. Snork says:

    Don’t ya think the computer manufacturers want the computers to eventually overheat so you’ll buy a new one? I’m still running a Pentium II until they get rid of Vista, then its new laptop time for me 🙂

  12. Brau says:

    Note to Ben: Either stop using your PC as an impromptu ShopVac or at least install a pleated hepa filter! 😉

    I’m amazed that it worked up until such a clogged state. Mine absolutely required I make a custom filter as the smallest amount of dust seems to have great impact.

  13. _Jon says:

    I once had a service call to clean a computer that was on the shop floor of a leather goods processing factory (back when that was done in the US).
    I couldn’t even see the components on the system board….

  14. Wayne D. says:

    An ESD safe vacuum is actually pretty easy to make. Run a bare copper wire up the hose and ground it to the earth ground in your vacuum with a 1 Mega Ohm resistor in series with it to limit the current that may come back UP the ground (e.g. lightning strike). Here is a link to the Woodcraft site that gives a good example of a wood shop dust collection system that minimizes static discharge. This is a good guideline for any shop vacuum, portable or not, that should be used.

  15. Nick Cody says:

    The way I clean them is to hold my vacuum hose 6-8″ from the surface and used canned air to blow the dust into the air. The vacuum then just sucks the dust out of the air without contacting anything. Keeps the mess down, and keeps dust from getting back in the pc.
    The trick I’ve found with canned air is to have 6 cans and once one gets cold and looses power swap to the next one in line. Then by the time the last one is cold, the first has come back up to room temp.
    I could only imagine what the power supply in that machine looks like.

  16. Matt says:

    Interresting article… I’m not sure your conversion from celsius to farenheit is correct though.

  17. Pete says:

    He doesn’t mean to say 16°C = 29°F. He means to say a change of 16 degrees Celcius is equal to a change of 29 degrees Farenheit.

    Farenheit degrees are smaller than Celcius degrees. If you forget, just figure it out. Freezing to boiling: F is 212-32=180 degrees, C is 100-0 = 100 degrees. So 1 degree C equals 1.8 degrees F. 16×1.8 = 29 to the nearest degree…

  18. Chris W says:

    If you turn your PC off when you’re not using it you won’t get much dust in it, and save energy. I never see more than a trace of dust in my PC even thought I have it on for a couple of hours every day.

  19. Skip says:

    You must be kidding, this computer must of been in a pig pen.

  20. dave says:

    The picture looks typical of what happens when an undersized CPU heatsink is used (to lower cost) and then a high(er) RPM and thus airflow, fan is used to compensate – because it is cheaper.

    OEMs tend not to use good filtration and positive intake for a few reasons.

    1) If it was good/edge-sealed filter panels, they would clog with dust far sooner than it would take to clog an entire system, the system would overheat to a critical level in a shorter period of time… remembering that all the OEM really cares about is that it works ok until the warranty period has elapsed.

    2) Placing even remotely decent filter panels on will reduce the airflow rate by a large %. Either you accept that and with it the resultant higher running temperatures as a new system, or you crank up fan RPM to compensate which makes it noisier. OEMs will do lots of things to avoid a noisy system if it’s a desktop rather than a server.

    3) To have positive case pressurization, and that with current ATX/BTX case designs, you would have a front intake fan pulling air in right behind a grill. This would place the fan far nearer to direct earshot from the user, allowing a far higher % of the noise the fan causes to be heard even if it were the same noise energy produced overall as with a different fan or pressure arrangement. The quietest arrangement is how most OEMs do it – only an exhaust fan on the rear, few if any side holes in the case panels, with the majority of the case intake through the front bezel.

    Also, consider that the PSU would be either exhausting out the heat it produces itself, or dumping that heat into the case where the other components are too. Thus, the PSU is going to exhaust out of the case. To have positive pressure you’d then need an intake fan with all that much higher airflow to compensate for the PSU exhaust, OR if you forget about the pressurization you have very minor additional case exhaust needed – unless the case exhaust is doubling as a fan to suck air through a duct away from the CPU heatsink.

    Personally, I’d rather a few additional dB of noise and have a positive pressure, WELL filtered system. Above I was not defending the choices OEMs make, simply listing a few reasons why they do it to keep cost low, noise low, and that their goal is the best out of box experience, not the best long term maintenance experience for the owner.

  21. JasonD says:

    The actual issue is “positive pressure cooling”. (Not talking about case-pressure, which is irrelevant unless you use filters and a high static-pressure blower-fan.)

    Pushing air through a restricted set of fins, is like wind trying to get through a screen. The more pressure, the less air can get into it. The pressure creates a “gate” stopping air behind from entering. Thus, the pressurized wet dust impacts the surfaces, and adds more restriction, collecting more dust.

    With negative-pressure cooling (suction of air through fins), air passes evenly through all fins, and the negative pressure stops dust from sticking, as it is being sucked-out. Even when restricted, the negative pressure will continue to “flow” through the “filter of dust”, which does NOT happen in a positive pressure cooler. It hits the dust-wall, and blows away from the fins.

    Proof of concept is, every single professionally designed piece of equipment uses negative pressure. Only cheap and poorly designed hardware uses positive pressure cooling. Every server, every telephone-gate, every medical device and most military devices. (Except those which “never” have that issue, or depend on other properties of high-pressure cooling, and have easy access to be regularly cleaned… like a car radiator.)

    A clogged cooler is a useless cooler. Doesn’t matter how efficient it is when it is clean, if it doesn’t stay clean for more than a month. Negative pressure coolers stay clean for years, and the unclean ones still function better than any dirty positive pressure setup.

    Also, positive pressure is “directed air”, with “massive turbulence” and “low static pressure”. Negative pressure is “evenly drawn in all directions”, and “high static pressure”, with “no turbulence”. Thus, you can’t “blow” air evenly across any restricted surface, even with shrouds. Yet, you can evenly suck air across every fin, with negative pressure. Thus, greater surface-area use.

    This is also why positive pressure setups REQUIRE massive amounts of air to “mix” with the hot air, in hopes that the mixture is cooler than the heated air. With negative pressure, all air is hot, and is instantly exhausted, never heating-up the surrounding air, and never “accumulating” more heat as it mixes.

    Positive pressure cooling is like trying to cool down a pot of water by emptying half, adding half cold, emptying half, adding half cold, emptying half, adding half cold… Thus redundant, and adding more heat to the system from the fans themselves, and the PSU which is drawing more power to run the fans.

    Negative pressure is like draining the whole pot at once, and pouring in fresh cool water all at once, over and over… The heat “flows” out, it does not “mix and half” to reduce temps.

    Seriously, one single fan is all that is truly needed. (Not any of the cheap fans they sell, which all run off 12v and use your PSU power… an actual exhaust fan, and actual structured cooling.)

    Two things that are cheap, easy to do, but not well marketable as a “water-cooled rig”, or “plug-n-play add-a-fan” crap they sell us, with lights and glitter and glow, and horrible overpriced/hyped function. They are selling heaters to desert dwellers, and you guys buy them up, talk them up, and fail to produce any actual justification for the expense. Not to mention the flood of published misinformation that reads, word for word, of the marketing hype that you guys were sold. I love it…

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