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

How to make your PC quiet

Run silent, run deep

By Poweroid

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


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





Power supplies


Graphics card heat pipes


Other products






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