Noisy PCs can create an uncomfortable work environment for users. The constant whirring and chirping sounds are distracting and can impede productivity, especially when there are many systems going at once. In this Drill Down, I will attempt to identify the culprits that generate noise pollution in PCs and show you how to build or modify a PC to make it quieter—without the use of a sledgehammer.

The problem
While a few computer manufacturers have started to account for excess noise in their designs and actually offer prebuilt low-noise PCs, the problem has continued to take a backseat to performance-driven and cost-saving designs that generally treat noise as a secondary issue. (Click here to read about sound measurements.) At the heart of the problem are the mechanical components used inside modern PCs. The main culprit here is the heat generated by power-hungry components and the cooling methods implemented to deal with this problem. The other significant source of noise is the vibrations generated by moving components within drive subsystems.

Noise solutions related to cooling
Since most computer noise is caused by the fans necessary to combat heat, and the heat is associated with high-power dissipating components, lowering the power requirements of a system is one method you can use to reduce noise. By reducing power consumption, you can reduce cooling requirements and thereby reduce noise. Now, let’s take a look at some alternative options to reduce the noise generated by cooling components.

Water cooling
Since fans are the main cause of PC noise pollution, you might ask yourself why you couldn’t just get rid of them completely and replace them with another cooling mechanism. Water cooling (or liquid cooling) relies on circulation of a fluid to dissipate heat generated by components. Companies such as Koolance are trying to widen the acceptance of water cooling by providing computer cases with prebuilt water-cooling solutions. The company provides easy-to-install cooling blocks for their cases that can replace fans on CPUs, video cards, and motherboard chipsets, and they even provide cooling for hard drives. However, there are limitations on the CPUs that can be used and the dimensions of the motherboards. Also, you will still need a power-supply fan, as the company’s plan to use liquid-cooled power supplies has been abandoned. This partial solution to the noisy PC problem doesn’t come cheap, so you should expect to add at least two to three hundred dollars to the total cost of each system.

Quieter power supplies
The fans on power supplies can be a source of clatter if the supply is not designed for low noise. Also, the higher the power rating of the supply, the greater the potential noise. However, you don’t want to sacrifice the advantages and stability of a quality power supply just to reduce noise, and you certainly do not want to underpower your system. That is why quality power supplies with efficient fans are now available that help to minimize excess noise:

  • ·        PC Power & Cooling: While their high-quality Turbo-Cool model is noisy, the company also offers an ultra-quiet Silencer model that offers similar specifications to the Turbo-Cool without the excessive noise. They are available in a variety of power ratings, up to 400W.
  • ·        Enermax: Some Enermax models come with adjustable fan control knobs that allow you to set the fan speed. With many newer motherboards, Enermax power supplies support a feature that will allow the motherboard to monitor the fan on the supply and turn it off when the PC enters sleep mode.
  • · QuietPC sells 300W and 250W ATX power supplies that it claims will operate under 26 dB(A). The 300W is an ATX12V power supply that can work with Pentium 4 systems. The specifications for these supplies indicate that they are of high quality.

If you already have a high-quality, albeit noisy, power supply, another option to reduce noise is to replace its fan with a quieter case fan. Many power-supply fans are the same size as 80mm case fans. You should use caution when you change out fans, as there will likely be high voltages in the capacitors of your supply even when it is unplugged. In fact, the inside of a power supply on a modern ATX-based system is the only component within the PC’s case that poses a significant shock hazard. The risk is minimal, however, as you shouldn’t have to touch anything within the supply except the fan and its leads when you are changing it. But be aware that replacing your fan will most likely void your warranty.

To replace a case fan, remove the supply from your system and open up its casing. Find the fan’s leads. (The fan’s leads are usually soldered to the supply’s printed circuit board. Do not try to unsolder them.) Clip the leads with a wire cutter, leaving plenty of length from the circuit board. Strip the ends of the cut leads and the ends of the leads from the new fan. After removing the supply’s fan and replacing it with your new fan, connect the leads together with the correct polarity using electrical butt connectors. Replace the supply casing, and you’re finished.

Case fans
Modern PCs have one or more case fans, and they can add to ambient noise significantly. To combat this issue, PC Power & Cooling makes an excellent low-noise case fan. (No, I do not work for them.) Their 80mm Silencer Auxiliary fans offer an impressive 27 cubic feet per minute (CFM) volume rate. PC Power & Cooling claims these fans rotate at 1,600 rpm and only generate 20dB(A). However, these fans do not support speed monitoring, which is a useful, but not critical, feature.

The case fan I use on my personal system is the Panasonic Panaflo 80mm. The Panaflo models move air in a funnel pattern and are said to be good for spot cooling. These fans, which are available in a variety of sizes, are designed for use in various electronics applications. Like the Silencer Auxiliary fans mentioned above, the Panaflo models do not support speed monitoring, either. case fans are also very quiet. The 80mm version is rated at 24 CFM and 21dB(A). However, these fans tend to be pricey, which is perhaps their main drawback. Nevertheless, they are high-quality ball-bearing case fans and make excellent replacements for noisy power-supply fans.

CPU fans and heat sinks
Processor fan and heat sink combinations are mandatory on today’s CPUs. CPU fans are generally smaller and spin at higher rates than case fans. This can cause them to generate a loud and persistent noise. Just as with case fans, there are many manufacturers of low-noise CPU fan and heat sink combinations. You should select these based on the CPU form factor and the amount of heat dissipation required by a particular CPU’s model and speed. The material, size, and construction method of heat sinks determine how efficiently they dissipate heat. Copper tends to be a better material for heat sinks than aluminum, yet it is more expensive. However, a more efficient heat sink may help reduce the burden on the fan to cool the CPU, thereby making things quieter.

I use Thermaltake fans, as they are high performance, quiet, and less expensive than other fans of similar quality. Thermaltake’s Volcano 7, for example, is designed for Intel Socket 370 and AMD Socket A and features a variable fan-speed control. Thermaltake rates them at 26 dB at low speed and 37 dB at the highest speed—5,000 rpms. Thermaltake also makes video and chipset fans. Some other companies that make low-noise CPU fans are:

Vibration noise solutions
Vibrations caused by the mechanical components within a PC may cause very loud noises when certain subsystems are being used. Component vibrations are also carried throughout the system case, which often produce a rattling noise.

Hard drives
Hard drives continually spin at high rates, and thus are a constant source of vibration. You might think that you could combat this problem by selecting a drive with a lower rotational speed, but that wouldn’t fix anything. Some hard drives are just plain noisy, even if they rotate at lower speeds—and, of course, lower rotation speed means less performance.

A cheap solution is to place hard drives in an enclosure. But the problem then becomes excess heat, as fast-spinning drives can become quite hot. Molex makes the SilentDrive enclosure, which is used to quiet noisy hard drives, but some drives just produce too much heat to be used in these devices.

A better solution is to buy a hard drive with noise reduction built in. For example, Seagate has created the IDE Barracuda ATA IV drives, using what it calls SoftSonic Fluid Dynamic Bearing motors. These are ultra-quiet drives that do not sacrifice performance. The drives in this series are all 7200-rpm Ultra ATA 100. Seagate rates its 80- and 60-GB Barracuda IV drives at 24 dB(A) idle, 28 dB(A) quiet seek, and 33 dB(A) performance seek. Its 40- and 20-GB versions are rated at 20 dB(A) idle, 24 dB(A) quiet seek, and 30 dB(A) performance seek.

Maxtor’s DiamondMax Plus 740X series drives deliver good performance, quiet operation, and are 7,200-rpm Ultra ATA 133 drives. These drives are available with standard ball bearings or with fluid dynamic bearings. Maxtor calls the fluid dynamic bearings Quiet Drive Technology Plus, and this version of the drive has a 27 dB(A) idle and 32 dB(A) normal seek mode average rating.

Despite recent bad (and sensationalistic) press due to problems with its 75GXP model, I still have a very favorable opinion of IBM’s Deskstar IDE drives. I find them to be reliable drives, and they are certainly fast for 7,200-rpm ATA 100 drives. IBM also offers a free download of the IBM Feature Tool utility, which you can use to change the drive’s Automatic Acoustic Management settings to the lowest acoustic emanation setting (Quiet Seek Mode),making them quiet enough to use in low-noise PCs.

Actually, most, if not all, current hard drive manufacturers offer low-noise hard drives. It is just a matter of going through the specs and finding one that will fit your needs for speed and capacity. A good source of information is

CD-ROMs, DVD-ROMs, and CDR-Ws can be extremely bothersome due to their motors spinning and changing speeds often. On many drives, the noise generated by this action is much more noticeable when the drive reaches top speed. Keeping your system silent while accessing a high-speed optical drive will be your toughest challenge. Unless you access CDs or DVDs frequently, this should not be a major problem. You can attempt to use slower drives or use software utilities that can slow down certain drives. Here are a few drives that you may want to try:

  • ·        Hitachi’s GD7500 DVD-ROM is a good-quality 12x DVD-ROM. It operates quietly except when it is transferring at 40x.
  • ·        BTC’s BDV 212B is a 12x DVD that can read CDs at 40x. Although the manufacturer claims that it has low operation noise, it doesn’t give any solid numbers.

Other companies known for making quiet CD-ROMs are LG and Sony.

Finally, some peace and quiet
When system manufacturers become truly serious about providing low-noise PCs, you will see a standardization of sound-level measurements. Until that day comes, unfortunately, the goal of the quiet PC system that is inexpensive, powerful, and uses no fans is unattainable. However, new low-noise components, though costly, will allow you to build a PC that is quiet enough for any environment.