A common question is what is a quiet computer? here is a quick look at some examples of built to order computers, their relative noise, and where I will head next when building future computers.
I could use my sound meter to give you exact figures but they are meaningless to most people. I will place the examples in order relative to other noises.
The devices and noise sources from quietest to noisiest.
- Antec NSK3480
- Fractal Design Array R2
- Noise from the kitchen
- Antec Sonata
- Noise from the laser printer when the cooling fan kicks in
- Television in the next room with the door shut
- Television in the next room with the door open
How quiet is quiet?
Sound is measured as Decibels, dB. No noise is 0 dB. A quiet room at night can be 20 dB or 25 dB while the same room during the day might be 35 dB. My test room is 37 dB today with no wind blowing and no birds singing outside the window. You will a difference of 3 dB. A change of 10 dB will make noise sound twice as loud and a change of -10 dB will make noise sound half as loud.
Your ears are damaged by the total volume of sound, which is the measurement usually used when measuring the noise from refrigerators, computers, and other machinery.
Your ears vary in sensitivity across the frequency range with a peak at about the frequency of children's voices and the small whiny fans used to cool graphics cards in cheap computers. Replacing a computer fan with a larger slower moving fan may result in the same movement of air and the same total volume of sound but be far less noticeable because the majority of the noise moved down to a less noticeable frequency.
Your ears and brain are more sensitive to some combinations of sound. Think of fingernails scratched across a blackboard and the dripping tap that keeps you awake all night in your cheap hotel room or cell in Abu Ghraib. A change to your hardware might remove just one frequency from a screeching sound and make the sound far less annoying.
One person might be annoyed by the constant whine of a disk drive then not notice the clicking sound when the disk heads move. Another person will hear the whine for only a few seconds before their brain ignores it but the click click click will send them screaming out of the room every time.
The case is an Antec NSK3480 with two deciding factors, there are slots for only two disks and the motherboard is a microATX size. Given the range of microATX cases and the size of modern disks, the Antec NSK3480 can work as a powerful desktop workstation or small server for everyone except people playing games requiring SLI or many disks. If you do not know what SLI is, you do not need it.
There are slots for two big external drives, typically used for DVD drives. I have a DVD burner in one of those drive slots and the other contains a disk in a rubber mount supplied with the case. Yes, there is space for two rubber mounted disks in the case but one is inside the second DVD drive slot and you have to choose what you want to use that slot for, a DVD drive or a disk. I chose a disk.
There is a small slot for a floppy disk or a card reader or an SSD, Solid State Disk. I might put an SSD in there for use as a really fast system drive.
There are two internal slots for disks and both have rubber suspension for rotating disks. The first, as already mentioned, is in one of the external DVD slots and the other is at the bottom of the case. I have disks in both. When I add the SSD, the two magnetic disks will be used in a RAID 1 configuration for reliability and speed.
The rubber mounts make the disks almost silent. I am using some Samsung disks and they make noise only when the disk heads are searching for data. Floating inside the rubber mounts, the disks produce no noticeable noise when rotating at idle.
There is one large fan at the back of the case and it is quiet. Antec insist on using fans with a three speed setting instead of making them temperature sensitive or controlled by the motherboard. One of my other cases has one big temperature controlled fan and, most of the time, it is quieter because it rotates at an incredibly slow speed when idle.
The case has a small efficient power supply with 80 PLUS efficiency and plenty of power for the small number of disks.
The motherboard is a microATX board with no fans on the motherboard. Gigabyte and some other manufacturers produce a wide range of microATX motherboards with no moving parts to make noise. You can get microATX motherboards for everything except multiple graphics cards, as used for games, and for some expensive Intel processors that are, again, only used for games.
The processor has a Zalman fan instead of the supplied AMD fan.
There is a big air vent on one side because Intel specified that somewhere. I covered the vent to stop noise escaping from the side. There is a big vent on top and that does not seem to do anything.
There is nothing else to make this computer quiet. A modern case would have a motherboard controlled fan and also have sound absorbing material on the case panels. Antec were the leaders for quiet cases back in 2007 when this case arrived. Today there are other brands starting to produce quieter cases but not in this size.
Fractal Design Array R2
The Fractal Design Array R2 based computer is next for quiet. This case has some sound deadening material inside and has one big fan with motherboard controlled speed. That motherboard controlled fan is the quietest fan in the room when the motherboard is idle then winds up to an annoying whine when the processor is heavily loaded for a while.
The case has rubber mounts for up to six rotating disks and a spot for an SSD. I have the system partition on the SSD for performance and use some magnetic disks in a RAID 5 array for lots of storage space. When I have time to tune the operating system and BIOS, I will set the magnetic disks to power down when idle for several minutes.
Overall the computer competes for the quietest computer when idle then drops back to second place when in active use. Better sound absorption and better noise isolation for the disks could move this case up to the top of the quiet list. I might look at buying sound absorbing foam for the sides of the case.
The Sonata was the first quiet case and arrived back in 2003. By today's standards, the Sonata is not quiet, it is just less noisy than most other brands.
The Sonata was the first mass produced case with rubber isolation of the disk drives for noise reduction. The Sonata uses rubber grommets that reduce transmission of the regular noise from an idle disk but not the large noise from an active disk. The Antec NSK3480 and some other cases use a larger suspension system to reduce a wider range of noise. Some really big high quality rubber bands would do a better job than the old Sonata grommets.
The Sonata has one large fan at the back but it is fixed speed instead of temperature controlled. The fan is not the noisiest component so I will not replace it.
The Sonata has a quiet efficient 80 PLUS power supply and the power supply is quieter than the disks, but only a little bit quieter. I will replace the power supply with something like the Seasonic M12. Another reason for replacing the power supply is the age. I had two Sonatas working continuously from 2003 and the other one blew up in the power supply, taking out the motherboard in the process. A new power supply will protect the motherboard and provide a little extra power for future upgrades.
The components in the case require a power supply of only 300 watts. The current power supply is 380 watts. Many of the power supplies with temperature controlled fans become extremely noisy when used near their maximum power. You can reduce the peak noise by using a power supply rated about double the minimum size. Offsetting that is the higher base noise of larger power supplies. If I use a 500 watt power supply, I get the lowest ongoing noise at idle and a medium noise when used heavily for a long time. If I use a 600 watt power supply instead of a 500 watt power supply, I add 2 dB (decibels) of noise to the idle level and most people cannot detect noise level changes of less than 3 dB. An increase to 700 watt would increase the idle noise by more than 3 dB. I prefer to keep the idle noise down while reading email and talking with friends.
The motherboard has no moving parts. The processor has a Zalman fan producing less noise than the original fan and there is room in the case to fit a bigger quieter fan. The processor fan is the third noisiest part after the disks and power supply. I might replace the fan after I replace the power supply.
In a room with a background noise of 37 dB, the computer produces a noise of 47 dB on the left hand side with the cover on and 57 dB in the same spot with the cover off. I could work on reducing the 57 dB on the inside of the computer or try to suppress the sound on the way out. Suppression usually takes a lot of materials and a lot of space. Reducing the noise at the source costs money and sometimes has the benefit of using less electricity, giving you a small cost saving, over the life of the computer, to offset the initial cost.
If there were no quieter cases on the market, I would keep the Sonata, add some sound suppression and diffusion to the side panels, add sound isolation between the case and the shelf it sits on, then work on replacing the disk isolation with something more effective, something like the system used in the NSK3480.
Ready made quiet computing components created a revolution back in 2003. We did not have to modify our computer cases to reduce noise and we could get a decent range of quiet fans. Today everything else in our office is quieter or missing. Our printers are quieter and, often, we leave them switched off for days at a time because we rarely print. Now our quiet computer is back to being the noisiest device. We are also loading our computers with far more components. We need to use better technology to tame the noise. Buy custom made computers and choose the right components from the start for minimum noise.