How I make PC's become silent
A lot of PC's make a significant amount of noise when they are turned
on. The hard disk makes the case shudder, the processor and
power fan constantly emit a fuzzy roaring. This may not be a
problem for a lot of users, but it can be a real problem for
others. Here are some tricks I used to decrease the noise,
sometimes even make it completely disappear.
Some internal parts of a PC use high electric tensions, 110
Volts or 220 Volts. This is dangerous. Switch the computer off
before touching parts inside. Actually just switching the computer down
is far not enough. The only real protection is to pull the power chord
from the mains away. Note some PC's on a lan/network can get high
tension from the network cables themselves. In such case pull the
network cables out too, before pulling out the power chord from the
Computers are sometimes very fragile. Everything you do to a
PC can destroy something inside it. Even just opening and
closing it. Be prepared to have to pay for another sound card
or another motherboard.
When doing something to the ventilator of a processor, keep in
mind most processors really
need to be cooled down.
Without adequate ventilation they can burn in a few minutes or at
least stop working. Keep also in mind the energy consumed
by a processor (and thereby the amount of heat it produces)
depends on what it is doing. Most of the time a processor
does virtually nothing. It just performs short calculation bursts
in order to start a program, calculate a printout or redraw a
window. In such
circumstances the air at the output of the cooling fan of my
processor is cold. But when you make it perform heavy calculations
during lenghty minutes, the air at the
output can become really warm. The amount of electric power
my processor once consumed even made the electric supply of my PC
go down! I had to get a stronger power supply.
Most computers have safety mechanisms against shortcuts and other
mistakes like plugging connectors the wrong way. They simply
switch off or hang at boot-up. Once the problem is fixed, they
will work back like before, with no damage. If this happens
while your are hacking inside your computer, it means you did a
big mistake and should let somebody else do it for you or do it
If your computer software start crashing and hanging after your
interventions, a probable explanation is you did something that
prevents a part inside the computer to be cooled down efficiently. This
Sometimes no screwdriver nor soldering iron is necessary. A friend's
computer was making a heavy ventilator noise. This was upsetting since
at the shop where he bought the computer it was noiseless. Actually the
problem was the shop environment was cold and my friend's room was hot.
So the processor was a little hotter and the motherboard decided to
switch the processor ventilator to maximum speed. Solution was to tune
the motherboard BIOS settings. We told the motherboard that the
should be allowed to run at a slightly higher temperature. Default
setting was 50 C° and we allowed 60 C°. Motherboard BIOS settings are
very easy to tune for an experienced technician. Just press the Del key
at startup and use your mind. If you aren't experienced maybe best
abstain. (A few months later my friend's computer started to hang once
in a while and he had to lower the temperature back down to 50 C° and
endure the noise.)
There are two kinds of fans: noisy ones and
silent ones, depending on how they were build. If you can,
just replace a noisy ventilator with a silent one. Be careful: some
ventilators are slower because they blow less air, so they will cool
On some PC's I just switched the power supply ventilator off by
cutting its wires (and wrapping them inside insulating
materials) or I put a small iron wire through its blades, from
the outside. This can only be done on PC's with a big power
source and a motherboard that consumes almost nothing, like early i386
PC's or some Mac boxes. Then the
power source and the PC inside do not need the hot air be
blown away. In order to test for this, lock the ventilator for
a few minutes then let it turn again. If the air that comes out
is cool or just tepid, maybe you can assume the ventilator
can be switched off forever. This trick can destroy your computer or
make it hang. Also you need to take into account the fact the computer
produces much more heat when the processor needs to perform lengthy
Most frequent intervention is I put diodes
in series on
the power wires of the ventilator. Each diode lowers the
electric tension the ventilator receives of about 0.7 Volts.
For example, 2 diodes put on a 5 Volts power source make the
ventilator receive just 3.6 Volts. This makes the ventilator
turn slower. The air flux reduction is not very important yet
the noise reduction can be remarkable.
- How many diodes have to be put on the ventilator power
wires has to be tested out. Start with two then add more of
them until the noise level matches your desires. (Be careful for the
temperature, sometimes the temperature is already a little too high
with no diode added.)
- Generally I put the diodes on the red wire (+). I cut the
wire somewhere and put the diodes between the two ends, each
diode soldered or latched to the next diode, like pearls on a
- Be careful: diodes let the current flow in one direction but
not in the other direction. If you put them on the red wire
then the ring on the diode has to be in the direction of the
- Do not forget to insulate the diodes before you close back the
Do not use too much insulation since this will also insulate the
heat flowing out of the diodes too and make the
diodes overheat. Thermoretractable plastic tubes are fine.
- Best use standard 1 A (one ampere) up to 5 A diodes, they will be
over-sized yet this is a security and diodes are inexpensive.
- Do not use a resistor; when the ventilator turns normally,
a resistor behaves roughly the same as a diode, yet when the
ventilator starts or is hampered by something, the resistor
tends to make no current available and then the ventilator stops.
Diodes on the contrary allow plenty of current to flow, so the
ventilator has enough force to start or re-start.
- Some power source ventilators do not use a 5 V or 12 V
wire. They directly use the 110 V or 220 V power. In such case
do not use diodes like above. Use pairs of big zener diodes
facing each other or use a 50 V varistor. Do not play with
electric components on 110 V or 220 V power sources if this is
not your profession.
An intervention I once did was to glue some pieces of plastic,
paper or cardboard to the ventilator blades. This slows them
down just like the flaps of a plane. Cleverly placed blades
make the ventilator blow roughly the same quantity of air while
turning significantly slower and with less noise.
Some recent processors that are placed vertically on the
motherboard are enclosed inside a black plastic box together
with a ventilator. The one a friend gave me was really very
noisy. So I tear the plastic and metal box apart, threw the
box and ventilator away, just kept the vertical printed circuit
with the processor and the peripheral circuits on it, and put
a standard heat sink & ventilator on the processor, latched
with silicon heat paste and a cotton string. (Be careful, just
aiming a ventilator at the processor surface is not sufficient.
The heat sink is necessary because it takes the heat away
effectively and distributes it amongst a forest of fins, where
it can be taken away by the slow air flux of the ventilator. In
order to be able to use no ventilator, less air should be used
but at higher pressure, forced above the processor surface
between the processor surface and a close plate.)
Provided the processor does not produce too much heat the
little heat sink & ventilator can be replaced by a huge heat
sink and no ventilator. Maybe even a sort of little chimney can
be used to make the air move due to the heating. This is expensive.
My P4 processor was cooled down by a little ventilator powered with 12
V. I replaced it by a huge yet standard 12 V ventilator and I powered
it on 7 V. With such a low tension feed and low turning speed it is
virtually noiseless. Yet it seems to output the same as the little
noisy ventilator since the processor remains cool under any
circumstance. Good deal. Yet a lot of cardboard cutting and taping to
adapt and duct the big ventilator.
While you're playing with ventilators, maybe check the temperature of
motherboard chips, graphic card chip and hard drive. Those parts
sometimes really benefit from a little ventilation. For my PC I bought
two standard PC 12 V ventilators for a few € and I powered them with
only 5 V. They turn very slowly, making no noise. I directed them
towards the graphic card and towards the hard disks. That makes them
cool down a lot
at virtually no cost and no noise.
I recently discovered that a ventilator makes much less noise if it
aspirates the air from the radiator instead of blowing the air towards
the radiator. I wrote a Web
The hard disk drive
Hard disks produce noise two different ways:
- Simply by being on and having the disks turning. This is
the noise that disturbs most.
- When the hard disk is accessed by the computer the
read/write heads are moved quickly above the disk surfaces.
This noise is more intense than the one mentioned previously, sometimes
sounds like a hammer being moved around inside a cooking pan.
Yet generally it is not disturbing. Some people even like this
noise because it allows them to know what their computer is
doing or if there is a problem.
Some computers can be tuned to have the hard disks be switched
off when they have not been used during a few minutes or tens
of minutes. Problem is they will need a few seconds to
automatically switch back on when they will be needed back.
This can be tuned through the BIOS tune screen at start-up
(generally called by pressing the Del key down) or through the
operating system control panel (power management).
Most of the noise the user hears are vibrations the hard disk
transmits to the rest of the case. My favorite trick is to
unscrew the hard disk and let it hang inside the computer, just
latched to its power and data connection wires (latched
somewhere). Of course this is not responsible way of doing, it
is only for people who are computer freaks and know they will
have to fasten their hard disk back in place before moving the
computer. More serious is to latch the hard disk somewhere
inside the computer through several thin nylon wires. Just like
a bug caught in a spider web.
When it is possible, the hard disk drive can be enclosed inside a
box, its wires coming out of the box through thin holes closed
by foam or the like. The hard disk can be held inside the box
by some little pieces of foam glued to the box. Be careful: the
box must not allow the hard disk to heat up. Best do this with hard
disks that keep cool naturally, put a ventilator inside the
box (like Russians did inside space probes), use a box
that lets heat flow away (thick aluminum boxes, for example)
or use a big box (an old fridge, for example).
Most of the noise a hard disk drive makes a PC produce is
transmitted by the computer case. So using a more solid
computer case, with thick metal or plastic armature and faces,
will probably help. Car furniture shops sell thick gummy plates
that are intended to be glued inside hidden car parts to lower
the vibrations and noise, perhaps this could help too?
This evening I'll try to put my hard disk inside a good quality
plastic bag and the whole inside a little bucket of water. The
plastic bag opening and the hard disk wires coming out of the
water. Very silly, but I thing it will give excellent results.
(It did !)
I never tried to make a CD-ROM drive become silent. All of them
are perfectly silent when they are not being used. Only some
high speed ones, 24x and above, roar when they are being
accessed by the computer. But while I was repairing one I could
notice following facts:
The small round plastic & steel piece that comes above the CD
to latch it on the motor's axis was build a wrong way. When a
CD is in and the round piece is glued on it by the magnetic
force of the motor's axis' magnet, the piece is able to move
sideways a few millimeters. This is the open door to
vibrations, due to the excentricity of the part. I suppose the
round piece had been conceived to match exactly on the motors'
axis when there is no CD inside.
There is a big fork-shaped iron plate above the CD, the
purpose of which is to hold the small round piece. It makes the round
piece move a little upwards and downwards when a CD is pushed
in or out. When a CD is turning inside the CD-ROM drive the
fork should not touch the round piece, letting it turn freely.
That CD-ROM drive's problem was that the fork-shaped plate
actually strongly touched the round piece, pulling the motor's
axis a few degrees away. This made the CD-ROM drive produce
noise and at the end even no more allowed it to turn properly.
I mend this by constructing blocks with two-components
hardening paste. The fork is now obliged to stop exactly in a
well-given position when a CD goes in. There is no more contact
between the two pieces when the CD turns. The round piece only
touches the CD and the motor's axis. From then on the CD-ROM
drive became perfectly silent.
Sometimes the best solution to avoid the noise produced by a
computer is to put the computer further away. Below the table
or a few meters away, inside a big box or in another room.
Cables can be found in computer and electronic parts shops to
allow the keyboard, mouse and screen be connected to a remote
computer. The longest connection distance between computer and
monitor I made was about 200 meters (not
because of the computer's noise).
Silent computers or computer parts can be bought.
Most yet not all recent hard drives are almost noiseless. Also lots of
CD and DVD readers and writers. Expensive power sources make their
ventilators turn very slowly and only power them up when there is a
danger of overheating.
These are links towards other pages about PC noise reduction and
companies selling components :
CG Consultant BV
The Silent PC
Silent PC mailing
Silent PC Review
NoiseLess Linux (French)
Lend your processor power for valuable scientific research: http://boinc.berkeley.edu
March 1 1999 till April 16 2006