CPU cooling is very important, a less than average CPU temperature prolongs
CPU life (up to more than 10 years). On the other hand, high CPU temperatures
can cause unreliable operation, such as computer freezes, or slow operation.
Extremely high temperatures can cause immediate CPU destruction by melting
the materials in the chip and changing the physical shape of the sensitive
transistors on the CPU. Because of this, never switch on the computer if your
CPU has no cooling at all. It is an extremely stupid thing to do. Turn your
computer on “just to test whether my CPU works” and you’ll likely find that
the CPU fries in less than 5 seconds and you will be off to buy a new one.
Most CPU installations use forced-air cooling, but convection cooling and
water cooling are also options. For traditional forced-air cooling, the heat sink
and fan (HSF) included with most retail CPUs is usually sufficient to cool the
CPU at stock speed. Overclockers might want to use a more powerful aftermarket
fan, or even try water cooling to combat the increased heat engendered by
overclocking.
Many retail HSF units have a thermal pad installed. These transfer heat
from the CPU to the fan, helping to diffuse the heat created by the CPU. This
pad is usable only once. If you wish to remove the fan from another CPU so
that you can use it on your new one, or need to take it off for some reason,
you will need to remove the pad and apply a thermal paste or another thermal
pad. Note that some of the cheaper pads can melt in unexpected heat and may
cause problems and potentially even damage if you are overclocking. In either
case, thermal paste is usually more effective, just harder to apply. If you plan
to do any high performance computing, or remove and replace the HSF often,
thermal paste is suggested. If you are planning on a long term installation a
thermal pad is often best.
Non-conductive thermal pastes made up of silicon are the cheapest and
safest, but silver-based thermal pastes sometimes perform better and carbonbased
ones perform better still. When applied improperly both can be conductive,
causing electrical shorts upon contact with the motherboard. A thin
properly-applied layer will usually prevent this problem, although some pastes
can become runny when they get hot. Users should also beware that many
“silver” thermal pastes do not actually contain any silver metal.
For quiet operation, start with a low-heat (low wattage) CPU. Processors
made by VIA, such as the VIA C3, tend to produce low amounts of heat, though
you will trade off a considerable amount of computing speed. The current
generation of duo core processors are more efficient than their predecessors, but
give off more heat than the Via processors. You can also underclock your CPU,
giving up some unneeded performance for some peace and quiet. Another option
is to choose a large copper heat sink with an open fin pattern. However, true
fanless operation is difficult to achieve in most case designs. You can position
a case fan to blow across the heat sink, or mount a fan on the heat sink. With
either choice, a large and slow fan will give better airflow and less noise than a
small and fast fan.
Some low-noise CPU cooling fans require special mounting hardware on the
motherboard. Be sure that the cooling fan you choose is compatible with your
motherboard.