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"Good neighbors keep their noise to themselves."

Noise Control in PCs - Reduction of noise in PCs

Article contributed by Poweroid in May 2004

PCs have becoming increasingly noisy as PC components have increased in speed and in the amount of heat they generate. This heat is normally dissipated via a variety of fans inside the case and these fans are the major source of noise. They are not the only source of noise though, hard disks have platters that spin at very high speeds, badly designed cases have side panels that rattle, and optical drives like DVD and CD drives generate noise too.

The cheapest ways of reducing noise in your PC – free options:

  1. Check that your PC case is standing flat on it’s feet. Reduce vibration between the PC and the table/floor. Experiment with rubber mats or even old mouse mats. Many cases need to take air in from the underside of the case so do avoid blocking any air vents. Avoid objects resting against the outside of your PC case.
  2. Ensure that internal components like hard disks, optical drives and other moving parts are secured down firmly and screwed down tight. Do the same with the side panels of your case.
  3. Use tie wraps to secure loose cables inside the case to prevent them from touching moving parts (avoid the use of rubber bands as these get brittle over time and they break into little pieces which get into fans)
  4. Vacuum the dust out of your PC. Dust clogs up fans causing them to get louder over time
  5. If your CRT monitor generates a buzzing sound or audible hiss then it is faulty, the manufacturer should be willing to repair/replace it
  6. Keep devices like mobiles – and other objects capable of electromagnetic interference – far away from PCs. Note that baby monitors, washing machines and a range of other household devices can interfere with your PC and/or cause your speakers to hiss, click or burst into pops.
  7. Depending on your operating system and modem you can usually set your modem to “silent” mode so it doesn't make a noise when dialing out.
  8. You could also experiment with the “Power” settings in the Windows control panel to set hard disks/monitors/fans to turn off in a pre-determined time if the PC is not being used. Read the Windows help file on what the various suspend/sleep and other modes mean. You can also turn off the "Windows" sounds i.e. the automatic wav files that are associated with Windows starting up, shutting down and running a variety of other tasks.

The cheapest ways of reducing noise – for PC Builders

  1. Use sleeve fans rather than bearing fans when possible
  2. Check dba ratings on all fans you use – from the CPU fan to the case/chassis fan to the PSU.
  3. Be aware that many components that come with fans are also available in no-fan versions - including motherboards with just a heat-sink and no fan on the Northbridge - and power supplies that are based more on music system power supplies and don’t need active cooling.
  4. When using fans use larger fans with a lower rpm. A 120 mm chassis (case) fan running at a low rpm will generate the same cfm (cubic feet per minute) of airflow as an 80 mm fan running at a higher rpm, but will generally make less noise.
  5. Avoid using PCI slot 1. Keep some distance between the graphics card fan and other PCI cards so air from the graphics card fan will not be obstructed.
  6. Some hard disks are sold as “Quiet” drives, they tend to not cost any more than standard hard disks. Shop around for quiet drives.
  7. 5400 rpm hard disks may not be quieter than the low noise 7200 or 10000 rpm disks. Higher rpm generally mean more whine BUT many of the higher rpm “performance” hard disks use fluid dynamic bearings and other clever technologies to run very quietly indeed.
  8. Route your cables carefully. When they block airflow they add to the noise.
  9. Choose your case carefully. Buying a quality case will allow you to add other sound control features later.
  10. Use the right wattage of PSU. If your PC requires a 350 Watt PSU it tends to be neither quieter nor environmentally friendly to use a 550 watt one.
  11. If you have grills on the case they may look pretty but if they have a chassis fan behind them they will disrupt the air coming out of the fan - and that makes a noise.
  12. Use filters over air vents for the air intake fans. Dust getting into the PC will make the fans noisier over time. (Washable filters are obviously preferable to the throwaway ones)
  13. Identify all the moving parts and make sure they are secured well and are not vibrating. This goes for everything from the fan screwed onto the CPU heat sink to the optical drives, hard disk, chassis fans and even the PSU. Use tie wraps and other securing mechanisms if necessary. They can even be used in addition to the normal retaining screws on devices like optical drives
  14. Identify other parts that could move or vibrate. Securing the hard disk firmly is not sufficient if the hard disk carriage/cage moves about or rattles. Secure the cage with tie wraps.
  15. Be always conscious that heat is a killer and if you compromise on heat dissipation then parts could burn out and the overall lifespan of your PC will be lowered.

Buying a quiet PC

There are basically two choices. You can either go for a lower performance PC that will probably not have all the latest features or go for no compromise PC with all the latest and most powerful processor, graphics card etc. The high performance PC will of course need a lot done to it to control the noise. Both options are described below.

Small form factor/integrated PC - compromise on performance/features: A lower performance PC generates less heat and needs less cooling so you have the minimum of fans, or no fans at all. 

There are several manufacturers of small form factor, mini-ITX, and other compact systems who integrate parts like the graphics card into the motherboard. While these machines are more than adequate for most tasks like word processing, browsing the internet, and even watching DVD movies they wouldn't be the first choice of an avid gamer and they wouldn't be up to the most demanding ray tracing or video editing tasks.

Integrated systems are cheaper to produce and should cost you substantially less than a fully fledged system. But apart from graphics performance are there any other compromises? Unfortunately, the answer is yes. These PCs tend to use lower end processors. Some of them don't even use the industry standard Intel and AMD processors, they use VIA CPUs (VIA is normally known as a manufacturer of motherboard chipsets but they do also produce some excellent budget processors that use very little power and generate very little heat). 

Other compromises involve giving up upgrade ability. On one of these systems it is highly unlikely that you'll be able to upgrade the graphics card or add a PCI card like a modem, network or TV card. They just don't have the space. If they do advertise a free PCI slot you may find that it's a "low-height/low profile" slot that won't take most standard PCI cards. 

If the CPU is integrated into the motherboard you may not be able to upgrade the CPU. These machines tend not to support the larger size RAM modules. You may also find that you'll have to make do with a single optical drive and won't have the luxury of both a DVD player and a CDRW. Limited space may mean you have only one optical drive. Sure, you can have a DVD Rewriter that covers all the jobs of a standard DVD player and CDRW but it will probably have to be a laptop style "slim line" DVD RW and there isn't that much of a choice in the slim line market. If a new and faster optical drive comes out it'll come in standard size for desktop PCs first and a slim line version may or may not follow several months later. 

The upside to having one of these machines is that they tend to look good, occupy very little space and can be squeezed into your music cabinet between the VCR and the stereo. You can also get them in silver/black and in matt/gloss finish to match most hi-fi equipment. And they make little to no noise. Do a search on the internet for terms like mini-ITX and you should find links to some of these systems.

Power PCs with specialist cooling products

It's possible to not compromise on performance or features but still have a quiet PC. Fortunately there are a wide range of products available to control PC noise. Several of them are discussed in the next page. However, do bear in mind that if you are building your PC yourself you could invalidate the warranty on several parts by modifying their cooling/heat sinks/fans... or replacing those parts. 

Also, when working with some of the specialist products you will invariably have a learning curve during which time you may damage some of these products or the PC components that they are fitted to. So do read the products' manuals carefully, visit their website, and browse through their user forum if they have one, and do stick to the book when fitting and using these products. On their own they will provide limited success with controlling the noise. Our recommendation would be to have your low noise/no noise PC built by an expert, by a company that does it for a living. They'll have several trade secrets they'd apply to further quieten your PC. Some of them involve techniques of air-flow control, cable routing etc that they have developed through years of practice. They also have the advantage of being able to test various configurations and setups in proper testing environments to see which products get the best result in your chosen configuration of PC. Their experience would be invaluable not just in reducing the noise but more importantly in ensuring that cooling is not compromised and that you get the maximum possible life out of the various components in the machine. Especially if individual components warranties are being invalidated it makes sense to have one company covering all the components, including the modified ones.

Cases: There are some cases designed to be quiet and marketed on that claim. Using a search engine for terms like “quiet cases” or “totally no noise cases” should point you in the right direction. Some of these cases are built like huge heat-sinks and use clever technology that will allow you to dispense with the use of all fans inside the PC, including processor, graphics card and other fans. There are other cheaper cases marketed as quiet cases that have an acoustic lining inside the case that absorbs some of the internal sounds. Either way having a quality case makes a lot of difference. Case rattle is one of the most common causes of PC noise (see section 1 above on “cheapest ways to reduce noise”)

Acoustic lining: A variety of acoustic lining products are available. Some of them are basic sheets of foam. Some are dual layer products with a thicker barrier material under a layer of sound absorbing foam. These lining products usually have self adhesive  backing. You can cut the sheets to fit along the inside of your case, peel the back off and fit them yourself. Some acoustic lining Acoustic foam products are as little as 3-4 mm in thickness, others as much as 17 mm. If space is restricted in your case you may want to go for the thinner (but less effective) products. Things to note: There are some cheap bitumen based products that degrade quickly over time and can be quite risky. Also, if your PC does rely extensively on the case body to dissipate heat (as is common with many aluminium cases) then you may want to create some additional airflow to compensate for the reduced cooling. You can do this via extra chassis fans. The blocks of foam in the picture fit into empty 5.25" and 3.5" drive bays to fill space that may otherwise be trapping hot air. Using these foam blocks reduces the volume of air within the box resulting in a faster "turnover" of air. 

CPU (Processor) fans: A variety of specialist fan manufacturers make low noise heat sink + fans combinations for processors. These involve using copper contacts to better transfer heat from the processor to the heat sink, using large heat sinks to quickly move the heat away from the CPU, and using large, low noise fans to blow air over the heat sink. Under 30 dba is usually considered quiet for these fans. The problem with larger heat sinks is that they don’t fit in all cases and they are particularly not suited to low profile desktop cases so please do check the available space above your processor before you buy one of these.


Water cooling: This has been gaining popularity despite the obvious downsides of combining water and electricity. As liquid absorbs and transfers heat more effectively than air does there is a practical argument in favour of water cooling. How it works is that the specially manufactured processor heat sink has two tubes connected to it. One feeds liquid to the heat sink and the other takes the liquid back to the external pump. Some cases manufacturers now provide the water cooling kits as options with some of their cases. One or two manufacturers also provide the water cooling kits integrated into some of their larger cases saving you the unsightly mess of having a pump and tubes on your table top. In either case though you will need to have an external "radiator" unit that dispels the heat.

The problem with water of course, is that unlike air cooled systems water needs to be enclosed. And it needs to stay enclosed – with no leaks - or it will damage the electronic components in your PC. This makes for equipment that is both bulky and expensive.

Other Cooling: Peltier coolers and other heat exchange systems have been tried in PCs with limited success. Issues like condensation etc cause problems in peltier solutions. Also, peltier coolers need your heat to be constant. If your PC isn't under constant, even use and/or you have energy saving features that trigger "sleep/suspension" modes or "CPU idling" you can't use a Peltier refrigerator/cooler; that excludes most PCs. Thermoelectric engineers have experimented with turning heat into electricity in a variety of other ways but most methods require large amounts of heat - about 200-300 degrees C - and even then only about 20% of the heat is converted to electricity. Other thermoelectric solutions consume a lot of power and/or generate substantial heat themselves and require active cooling. 

Hard Disks: Apart from the fans in a PC hard disks are the only moving parts that are always moving (optical drives only move when you have a DVD or CD in them). In 2004 it’s possible to buy/build a PC without fans but you still can’t have one without a hard disk (unless it’s a thin client on a network – but that’s another story). And hard disks are usually noisy. Your data is stored on platters on the disk and there are reading heads in the drive that write this data to the platters and access/read the data when you need it. The spinning of the drive causes the whining noise you get with hard disk. The head moving about causes the trashing sound. Hard disks started off at relatively low speeds. The fastest hard disks were SCSI disks at 7200 rpm spindle speeds but these were used only in server environments. However, 7200 rpm reached the desktop PC a few years ago and newer desktop hard disks even run at 10,000 rpm. That’s a lot of revolutions per minute. Fortunately, these advances in hard disk speeds have been accompanied by new technologies to limit the noise the disk generates. Most hard disk manufacturers now either offer a range of quiet disks or use special quietening techniques on all their disks. If you’ve got an existing older hard disk that you need to control the sound on - or even a newer disk that’s just too noisy for you - here are some products that may help.


Hard disk mounts: These are L shaped metal blocks with rubber in between. Hard disks typically have four contact points with the case i.e. at the four holding screws. If you have a spare 5.25” bay however you can use these mounts and move the hard disk to the larger bay. At each corner of the disk you’ll have one L shaped mount screwed on to the hard disk and one on to the bay ensuring that the metal from the hard disk doesn’t touch the metal on the bay and therefore reduces vibrations transferred to the case.


Hard disk heat sinks, like in the picture here, serve two purposes. They have four rubber rings that act like the mounts above which prevent the hard disk coming into direct contact with the case. They do also have a heat sink consisting of a collection of copper pipes that dissipates heat from the higher spindle speeds drives.

Enclosures: Some manufacturers sell complete enclosures for your hard disk. An enclosure will typically fit in a 5.25” bay and completely contain your hard disk i.e. a little box into which your hard disk vibration and noise disappears ... theoretically. Please do be very, very careful with these enclosures though. Check that they are rated to handle the spin speed of your hard disk and are capable of getting rid of the heat the hard disk generates. Some enclosures dissipate the heat via one or two little fans. And, as with any fans, these will generate some noise themselves so you’ll have to balance that against the saving of hard disk sounds.

Recently there have been major advantages in storage technologies. Flash memory cards have been getting bigger and bigger. Soon there will be storage devices like flash memory cards that will hold an entire operating system and your other files thus dispensing with the moving hard disk altogether. In fact such devices do exist right now but they are so horrendously expensive that they are used only in very select situations like space exploration and military applications. (At the last check a half decent size “disk” was $40,000).

Power Supplies: In many PCs this is the component that generates the most noise. When choosing a PSU for your PC shopping around can save you a lot of sound. Manufacturers of quality PSUs normally have a noise rating listed along with the technical specs. Further, using the right wattage of PSU for your PC does help, if you don’t need a 550 watt power supply, why buy one. It will probably make the same amount of noise even if you are only demanding 200 watts of power out of it. If the budget stretches to it there are some PSUs now available that are completely fan-less. These tend to come as standard on very expensive cases that are marketed as quiet cases, but some of them are also available for purchase to fit in any standard PC. They dissipate heat via a large radiator type heat sink that sits outside the PSU and outside the PC. Some of the heat sinks stick out a few inches behind the computer.

Graphics card “VGA heat pipes”:  Performance graphics/video cards do of course generate a lot of heat. In fact the processors on today’s high end graphics cards have more power than the main CPU in any PC you’ve had for a few years. Because of the international standardisation on size and location of PCI and AGP cards the graphics card fan has to be fairly small. This of course means that it needs to spin faster to keep the card cool. Some cards have high performance RAM on their flip side and sometimes these need active cooling too. The best route to take with graphics cards is - as with the PSUs described above – if you don’t need the power then settle for a lower tech option. But if you’d still like to lower/remove the sound from the graphics card’s fan you’ll have to shop around for a VGA heat pipe like the one in the picture below. To fit it you’ll have to remove the heat sink and fan your graphics card came with (and lose the manufacturer’s warranty on the card for “tampering” with it) and fit a VGA heat sink instead. This spreads the heat over a much wider surface area and provided you have sufficient airflow over the VGA heat sink/heat pipe you may get away with not having a fan to cool your graphics card down.


Other products

Thermal paste: This is a vital product in any PC builders' kit. It’s normally applied between a processor and the heat sink and helps conduct the heat away from the processor. Too much of the paste is counter productive, you need only a thin film.

Chassis Fans: The most popular size of chassis fan is the 80 mm. However, 120 mm fans are now becoming quite popular – and therefore available - because they do tend to generate less noise. Not all 120 fans may fit on your case as the case may have screw holes for only the 80 mm size. There may be adaptors available that will allow you to use a 120 mm fan in a location normally reserved for an 80 mm. Some of these chassis fans are quite clever; they come with ducting that leads to the CPU to provide a more direct route for CPU heat to leave the case.

In quality cases you will normally have at least one or two chassis fans at the front of the case drawing cool air in. Often this air is dragged in over a dust filter or a grill. This air movement through the filter/grill can cause a small bit of noise. In our opinion it’s not worth removing an intake filter to reduce sound. The filter does serve an important purpose. Removing a filter may well save you a fraction of sound but the extra dust going into your PC and settling on fan bearings will more than negate that benefit.

Chassis fans range from about 15 dba to about 30 dba. Quality case manufacturers who provide chassis fans tend to provide fans that generate less than 20 dba.

Regulators: Most electronic shops will stock a variety of devices that can control fan speeds via resistances. It is possible to have all the fans in your PC, from your PSU to the CPU to the chassis fan running only at the lowest rpm they need to run to keep the relevant parts within your pre-defined operating temperature range. Automatic adjustments of power to a fan can make it spin faster or slower and these automatic adjustments could be based on the output readings from temperature sensors. These are all products for the professional or the very keen enthusiasts. Attempting to fit them yourself may result in some burnt out components before you get fully familiar with them and fully competent at setting them up.

The bad news and the good news

The never ending quest for more performance out of computer systems invariably results in hotter components that require more and more cooling which whether done by fans or water pumps increases the noise generated. The good news is that boffins at chip manufacturers are constantly looking at new ways of designing chips to consume less power and generate less heat. 

There are a lot of interesting ideas and concepts being tested. One of them involves “nano-lightning” i.e. the production of an air flow along the surface of the heat sink by ionising and pumping air molecules using minute electric currents. Electrodes containing carbon nanotubes have a tiny charge applied to them resulting in electrons being knocked off air molecules and the consequent positively charged ions being attracted towards a negatively charged electrode …taking heat with them. This flow of ions is then controlled to move the heat away from the surface of the heat sink. Viola, no fans. But this, and other innovations, are still in the testing stage and have a long way to go before reaching the market.

The researchers will eventually develop systems for transferring heat out of PCs without using any noisy equipment like fans and pumps. In fact, here’s hoping they develop ways of increasing PC speed using techniques that don’t involve the creation of heat in the first place. That, together with advances in solid state technologies involving storage devices with no moving parts, should make for some pretty silent computing in the future. But till then we hope this article has helped.

Article contributed by Poweroid


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