Original URL: https://www.theregister.co.uk/2004/05/17/quiet_pc_guide/

How to make your PC quiet

Run silent, run deep

By Poweroid

Posted in The Channel, 17th May 2004 14:52 GMT

PCs are becoming noisier. As components have become faster, the heat they generate has increased. Since that heat is traditionally dissipated using a variety of fans inside the case, the number and size of these fans has grown too, to the extend that they have become the major source of noise within a PC.

They are not the only source of noise. Hard disks have platters that spin at very high speeds these days, and optical drives like DVD and CD units generate noise too. Badly designed cases have side panels that vibrate.

If you're tired of the racket your PC is making, you have two choices before you. You can either go for a lower performance PC that will probably not provide all the latest features - or go for no compromise PC with all the latest and most powerful processor, graphics card and so on. Of course, the high performance PC will need a number of modifications to control the noise.

Small form factor PCs

A lower performance PC generates less heat and needs less cooling so you only need the minimum of fans - and possibly or no fans at all.

There are several manufacturers of small form factor (SFF), mini-ITX and other compact systems who integrate parts like the graphics chip onto 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.

These PCs also tend to use lower-end processors, and offer very limited scope for future upgrades. If the processor is built onto the motherboard, you may not be able to replace it at a later date. It's highly unlikely that you'll be able to upgrade the graphics card or add a PCI card like a modem, network or TV card, for example. 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 a standard PCI card.

These machines tend not to support 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 CD-RW. Sure, you can have a DVD-/+RW that covers all the jobs of a standard DVD player and CD-RW but it will probably have to be a laptop-oriented 'slimline' unit. If a new and faster optical drive is launched it will ship in standard size for desktop PCs first and it may be months before a slimline version follows.

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 or 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

It's possible to make no compromise on performance and yet still have a quiet PC. There are a wide range of products available to control PC noise, most of them offered as user-installable upgrades. But do bear in mind that if you are building your PC yourself you could invalidate the warranty on several parts by modifying whatever cooling systems they ship with or replacing any of their parts.

More importantly, when working with some of the specialist products you will invariably have a learning curve to make during which time you may damage some of these products or the PC components they are fitted to. Do read the products' manuals carefully, browse through their user forums, and do stick to the book when fitting and using these products.


Zalman quiet PC caseThere are some cases designed to be quiet and marketed on that claim. Using a search engine for terms like "quiet cases" or "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. There are other, cheaper cases that have an acoustic lining that muffles some of the internal sounds. Either way, having a quality case makes a lot of difference. Case vibration is one of the most common and easily resolved causes of PC noise.

Case lining foamA variety of acoustic lining products are available. Some of them are basic sheets of foam, others 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 products are as little as 3mm in thickness, others as much as 10-15mm. If space is restricted in your case you may want to go for the thinner (but less effective) products.

There are some cheap bitumen based products that degrade quickly over time and can be quite risky. If your PC relies 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.

Processor fans

CPU fanA variety of specialist fan manufacturers make low-noise heat sink and fan combinations for processors. These involve using copper contacts the better to transfer heat from the processor to the heat sink, using large heat sinks to quickly dissipate that heat to the air above the processor, and using large, low-noise fans to move the heated air away from the processor. What's a good fan noise rating? Under 30dB is usually considered quiet.

The problem with larger heat sinks is that they don't fit in all cases and are particularly unsuitable for low-profile desktop cases. Very often the location and size of your processor makes it impossible to fit one of these heat sinks. Furthermore, in dual-processor rigs, you may find that your CPUs are too close together to be able to use these (generally) quite wide heat sinks.

Water cooling

This has been gaining popularity despite the obvious downsides of combining water and electricity. Liquid absorbs and transfers heat more effectively than air does, so there's a practical argument in favour of piping water over the CPU instead of air.

Some cases manufacturers now provide the water cooling kits as options with some of their cases, and one or two others offer 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 coolers

Peltier coolers and other heat exchange systems have been tried in PCs with limited success. Condensation can cause problems, and you need your heat output to be constant. If your PC isn't under constant, even use or you have energy-saving features that trigger system sleep modes, you can't use a Peltier 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 per cent 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

Today, it's possible to buy or build a PC without fans but you still can't have one without a hard disk. And hard disks, with all their moving (often constantly) parts, are usually noisy. Desktop 7200rpm drives are now commonplace, and newer desktop hard disks even run at 10,000rpm. Fortunately, these advances in hard disk speeds have been accompanied by new technologies to limit the noise the disks generate. Most hard disk manufacturers now either offer a range of quiet disks or use special quietening techniques. If you've got an older hard disk, here are some products that may help.

Hard disk mountsHard disk mounts These are L-shaped metal blocks with rubber in between. Hard disks typically have four contact points with the case, at the four holding screws. If you have a spare 5.25in bay, you can use these mounts and move the hard disk to the larger bay. At each corner of the disk you'll have one 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 doesn't transmit vibrations to the case.

Hard disk heat sinkHard disk heat sinks These serve two purposes: they have four rubber rings that act like mounts to prevent the hard disk coming into direct contact with the case, and they have a heat sink consisting of a collection of copper pipes that dissipate heat from the higher spindle speeds drives.

Enclosures Some manufacturers sell complete enclosures for hard disks. An enclosure will typically fit in a 5.25in bay and completely contain the drive, sealing in vibration and noise. But 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 heat using one or two little fans. As with any fans they generate some noise themselves so you'll have to balance that against the how far the enclosure quietens the disk overall.

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. And if you don't need a 550W power supply, don't buy one. It will probably make the same amount of noise even if you are only pulling 200W out of it. If your 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 heat pipes

Graphics card heat pipePerformance graphics cards 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 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 to settle for a lower tech option if you don't need the power. But if you'd still like to lower or even remove the sound from the graphics card's fan you'll have to get a VGA heat pipe. To fit it you'll have to remove the heat sink and fan from your graphics card, voiding the manufacturer's warranty on the card. The heat pipe spreads the heat over a much wider surface area and provided you have sufficient airflow over the card 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 builder's kit. It's normally applied between a processor and the heat sink and helps conduct the heat away from the chip. Remember, too much paste is counter-productive - you need only a thin film.

Chassis fans The most popular size of chassis fan is the 80mm. However, 120 mm fans are now becoming quite popular because they tend to generate less noise. Not all 120 fans may fit your case, however, but there may be adaptors available that will allow you to use a 120mm fan in a location normally reserved for an 80mm unit. 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 which can cause a little noise. In our opinion it's not worth removing an intake filter to reduce sound. The filter serves too important a purpose. Removing a filter may well save you a little noise, but the extra dust going into your PC and settling on fan bearings will more than negate that benefit.

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

Regulators Most electronic shops will stock a variety of devices that can control fan speeds. It's 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 fan power can make it spin faster or slower and these automatic adjustments can 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 future

The quest for maximum performance invariably results in hotter components that require more and more cooling. Whether that's done with fans or water pumps, it 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' - 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 controlled to move the heat away from the surface of the CPU. 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.

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.

The cheapest ways of reducing noise

  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 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. 5400rpm hard disks may not be quieter than the low-noise 7200rpm or 10000rpm 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 grilles 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.

We would like to thank Best Price Computers for their contribution to this article. BPC has been specialising in low-noise systems since 1995. Its award-winning Poweroid range of hand-built quiet PCs are aimed at enthusiasts.

Copyright © 2004, BPC