Reduction of noise in PCs

As the UK experts on building quiet PCs at the performance end of the market we were approached by one of the world's largest anti-noise organisations with a request to come up with some advice and tips on building low noise/no noise PCs. The content in this section of our site is what we compiled for them. We hope you find it useful.

PCs have become 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.

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