What Causes Computer Systems to Heat Up
While most components in your computer system generate heat, some components cause more heat than others.
For example, your Central Processing Unit (CPU) which is most in use
even during normal operations is one of the main components that needs
proper cooling to stay functional. Your Graphics Card (Graphics
Processing Unit, GPU,) also needs special cooling, usually already built
into the card itself. This is especially true for gamers, where the GPU
is under a heavier load than it would normally be.
Another component that can generate large amounts of heat is the
computers’ Random Access Memory (RAM). While generally this is not as
much of an issue, some newer and faster RAM modules will come with a
pre-assembled heat sink to help offset the extra heat that is caused by
the faster speeds.
With all of these components each causing heat, they also heat each
other up. A CPU’s heat might further raise the graphics card’s heat and
vice versa. Heat is then dissipated through cooling mediums, including
the case itself, airflow, heat sinks, etc.
Above: Dusty Heat Sink
Heat can also be caused by poor airflow. If airflow is obstructed by
excess dust, hot air cannot be vented out of the system, and builds up
inside, as shown in the image above. Obstructed airflow can also be
caused by improper orientation of fans and components being in the way.
Aside from poor airflow, improper application of thermal compounds
can cause heat sinks to lose efficiency and cause more heat within the
system.
So How Do You Keep Heat Under Control?
There are many ways to keep different components from overheating.
I’ll go over each of the most common cooling methods used in today’s
consumer computer systems — heat sinks, fans, and thermal compounds —
as well as some less common cooling methods that are not yet fully
mainstream, but still an important part of high-end computer systems
(liquid cooling).
Heat Sinks
One of the most common cooling components is the heat sink. Heat
sinks can be found on most computer components including the CPU,
Graphics Cards, RAM, and other integrated circuits.
There are two types of heat sinks:
passive heat sinks and
active heat sinks.
Above: CPU and chipset heat sinks
Passive heat sinks are essentially just pieces of aluminum, or more
recently, copper, affixed using thermal compounds onto a computer chip
that normally produces heat. Heat is then transferred through the
conductive thermal compound into the metal, and is redistributed away
from the chip itself. While this method works well for older CPUs and
chips, newer and faster ones will require a more powerful cooling
solution, such as an active heat sink.
Active heat sinks are similar to passive ones, except they have a fan
attached. The fan helps to pull heat away from the heat sink allowing
it to cool more effectively. You will usually see active heat sinks in
graphics cards, and even larger active heat sinks in CPUs. Active heat
sinks do require more care, as with the addition of a fan, dust is more
susceptible to enter the heat sink and will require cleanings and care
more often.
Fans
Fans, more specifically, case fans, help to cool your computer case
by (usually) pulling cold air in through the front of the PC case, and
blowing it out of the back.
This is not always the case though, as each PC builder has their own
cooling preferences, and others may actually add in case fans causing
their heating methods to be counterproductive. An example of a
counterproductive fan setup would be all fans pulling air in. This can
cause an excess of dust, as well as no way for heat to escape.
Above: Case fan with blue LEDs
Aside from case fans, there are also other types of fans available.
PCI slot fans, or blowers, are one way to increase the flow of air
out of the back of the PC case. Hard drive (HDD) fan modules are usually
made up of two small fans attached to the exposed side of an internal
hard drive; this helps to pull heat away from faster or more active hard
drives. Most internal power supply unites (PSUs) will have an internal
fan pulling air in and another blowing air outside of the computer case.
Fans can also be found as part of active heat sinks in CPUs, graphics
cards, and chipsets.
The most common fan size ranges between 40mm and 140mm; though fans
as large as 240mm are starting to emerge in the mass market and in
specialty cases.
Water Cooling
Water cooling is generally only used in high-end systems and gaming systems.
Water dissipates heat more efficiently than heat sinks and fans.
Water cooling systems consist of a pump that pumps water across multiple
components within the system. Most often, water cooling systems work to
actively cool the CPU and graphics card, but modular systems allow the
connection to other components within the PC. Water cooling can also be
much quieter than using more conventional cooling methods like fans.
Above: Liquid cooling
While there are many upsides to using water cooling, there are also a few major downsides.
Not only are water cooling systems much more complex, but they are
also a more dangerous build if not done properly. Even a small leak can
turn disastrous. If a leak is present, the coolant can damage internal
components including the motherboard itself.
