The CPU fan and the hard drives are probably the prime offenders, with power supply and case fans following closely on their heels. Unfortunately, as heat builds inside the case from faster components, simply plucking out fans isn't the real answer to stopping that buzz. In fact, aside from simply never hitting the power switch, there may be no real way to make a computer totally and utterly silent. There are, however, several ways to make one quieter.

Antec, manufacturer of computer cases, power supplies, and fans, recently released its line of TriCool fans in 80mm, 92mm, and 120mm versions. The TriCool's claim to fame (along with models that use ball bearings) is that they're speed selectable, allowing you to customize your noise level to match your cooling needs.

Silence Is Golden
But first a quick primer on noise. The average alarm clock, at two feet, will typically wake you to 80 dBA of sound. If you listened to it, non-stop, for more than eight hours, you might not be able to turn the noise off in your head afterwards. In contrast, Antec's standard 80mm black case fan is rated at 30 dBA, which is about as loud as sitting in your average library.

If heat isn't an issue for you and sound is, you can replace your standard black case fan with a TriCool 80mm model. At top speed, it pushes the same 34 cfm (Cubic Feet per Minute) air flow and is rated the same 30 dBA as a standard fan. Hit the slide switch to drop it down one speed and you lose only 8 cfm of cooling but the noise level drops to 24 dBA. Take it down one more notch and you drop to 20 cfm and only 18 dBA, which is lower than a whisper at five feet. (Normal breathing is rated at 10 dBA.)

When heat is also a problem, the solution becomes more complex -- and costly. Most, if not all, computer cases running 80mm fans won't let you easily or practically install a bigger fan. You'll need to spring for a new case and it might as well be one that holds the biggest fan: 120mm. While they were difficult to find at one time, the new BTX form factor cases all support 120mm fans, so you're in luck.

What happens at 120mm? At top speed (2,000 rpm), Antec's TriCool is rated at 79 cfm -- more than two and a quarter times that of an 80mm fan -- but does so at the same 30 dBA rating. Slide its speed switch down one notch to 1,600 rpm and you're still pumping 56 cfm -- about 65 percent more than that 80mm fan, but the noise drops slightly below the deafening library level to 28 dBA. Shift it into third, 1,200 rpm, and it still moves 5 cfm more air than a stock 80mm fan but, at 25 dBA, it's quieter than a library and only slightly louder than that five-foot whisper.

Best of all, replacing case fans is simple. They're either screwed to the panel or isolated on rubber mounts. Once you've powered down your PC and unplugged the fan, just clip off the mounts or undo the four screws. The Antec replacements are screw-ins and all mounting hardware is supplied. The TriCools are also dual-power, having both a four-pin connector for a power supply and a three-pin plug that will mate to the fan power connectors on your motherboard. And your motherboard can monitor the fan speed if it supports that capability,

Bill O'Brien can be blamed for more than 2,000 articles on computers and technology topics. With his writing partner, Alice Hill, Bill jointly authored "The Hard Edge," the longest-running (1992 to 2004) technology column penned by a techno duo. For more, go to www.aliceandbill.com.