Glenn Garrett freely admits that the noise computers make is a personal obsession. It began in 2000, when he bought a new machine with an AMD Athlon 600 processor.
“My own machine was extremely loud,” he says, pausing to reminisce about the silent computers of the 1980s, “and every time I upgraded it, it got noisier.”
The first PCs brought in fan-cooled power supplies, and the Pentium’s faster clock speeds required additional cooling just for the CPU. Now, even graphics cards have their own cooling.
The Athlon 600 was no exception. “It came with two fans, and I thought this was getting ridiculous.” At the time, he says, nobody was paying attention to noise; everyone just wanted a faster computer. So he started a business, QuietPC (quietpc.com) to find, review and sell quiet computer components from his home in North Yorkshire. He thought the business wouldn’t last long – surely manufacturers would jump on the issue and make it a selling point? But so far, “We’re still doing OK. Manufacturers don’t pay attention.”
Mainstream issue
Nonetheless, computer noise is becoming a mainstream issue, especially since people are beginning to build media centre PCs into their home audio/video systems. And who wants to watch a great movie or listen to a fine piece of classical music over a high-pitched whine in the wrong key?
There's a simple rule in computer noise: the bigger the fan, the less annoying it is. To shift air, small fans have to run fast, which means more high-pitched noise, and it’s the higher frequencies that bug most people. A six-inch fan can run slower and generates sound at a lower pitch than the two-inch ones you’ll find attached to processors to cool them down.
And modern processors generate a lot of heat; you hope all those fans and heat sinks reduce their operating temperature to under 50C. But others find it’s not the computer itself but the screen that’s the source of trouble. Traditionally the problem has been the high-pitched squeal CRT monitors produce as a function of the frequency of their refresh rates.
“I’ve managed to train a few colleagues to turn theirs off when they go home, but otherwise I have to go around turning them off myself if I’m working late,” says Mark Wigmore, who uses the CIX online conferencing system.
The arrival of LCDs has solved that problem for some – but not others. “I find I’m very sensitive to the whistle/scream of backlight transformers – the things that make flat screens work,” says IT consultant Steve Cassidy. Sometimes you can solve this problem by altering the direction from which you’re looking at the screen, though then you may be unable to see it.
Why not just ignore it? “The human auditory system adapts quite quickly,” says Tom Stewart, founder and director of the ergonomics consultancy System Concepts. “But the noise can contribute to our overall stress levels and tends to make us tense generally”.
However, he says, hearing damage in modern offices is “unlikely”. Most offices are closer to 40db to 55db.
How loud is that? A whisper is perhaps 30db. A quiet room is 40db. Moderate rainfall is 50db. Normal conversation is about 60db. A PC that made that much noise would quickly find itself being beaten with a baseball bat. PC Pro magazine, which commissions acoustic testing for its group reviews, says the high end in recent tests has been 47dB – somewhat louder than an average refrigerator, at 45dB.
Testing is also complicated by the fact that the noise of a given PC varies a lot depending on what it’s doing.
The PC that’s quiet when idling may emit an unpleasant screech when the hard drive is seeking data or the DVD drive spins up. The upshot is that although some manufacturers, such as Hewlett-Packard, do give noise specifications, it’s hard to know what the machine will really be like in real life.
Comparative tests
PC Pro’s testing is carried out by the Milton Keynes-based company Intertek, which tests a wide range of consumer goods. Natalie Pickering, the technologist who does the computer testing, says the company uses a “semi-echoic” room – that is, a room with some echo so it’s more like a very quiet (27db) normal room. It turns out that building a machine these days is a colour-by-numbers affair, rather than the difficult engineering project it used to be. You buy a bunch of components (case, power supply, motherboard, processor, memory, graphics card, hard drive and DVD drive) and plug them all together. Plugs are coded to go in only one way, and motherboards come with helpful manuals and diagrams.
Plus, dozens of websites (for example, pcmech.com/byopc) have detailed general instructions, and dozens more have advice about your specific components. Any problem you run into has probably already been solved and documented.
Why do PCs get hot?
Computers famously work in 1s and 0s; in reality, these are high and low electrical voltages that are applied to and then stored in the millions of transistors that makes up the processing units in a PC.
Every time a transistor switches state, which is every time any bit of data is changed, electricity must flow through it – and each time, a little heat is generated as electrons collide. The faster the processor, the more often the transistors change states – and the more heat the processor generates. This must be dissipated for the processor to work reliably. Current processors run hot enough that the processor has its own heat sink and usually a fan, too. These conduct the heat into the airflow created by the fans incorporated into the computer's case design. Newer designs attempt to make faster chips more efficient, so they are not only cooler but also use less energy.
