06/10/2017
The power coming into a
computer is the most critical
component, and it may be one of
the most overlooked. It is just
taken for granted that it will
always be there and working
properly. A top of the line
processor and ultra powerful
video card do nothing if a system
does not receive the ample,
stable power it claims. Having
quality components providing
and regulating the power
supplied to a computer is critical,
and this brief overview looks at a
few areas worth consideration.
Power Supplies
Computer power supplies take
the high (110V or 220V) DC
voltages from an electrical outlet
and convert it to the various
lower AC voltages required for a
system to operate. The typical
voltages required inside a
computer are 3.3V, 5V, and 12V,
where the 3.3V and 5V lines are
generally used to power circuitry,
and the 12V line provides power
to run items such as hard drives,
optical drives, and cooling fans .
Power supplies are sold in terms
of their total power output, in
terms of wattage. Choosing the
correct power supply means not
only finding one that will
provide enough power for all of
the components connected to
the system, but also one that is
the correct size physically, has
enough connections for typical
drives and fans, and if necessary,
that also has special connections
for things such as Serial ATA
drives and modern video cards.
Choosing a power supply with
enough power should not be
much of a problem, as having
more power than you need is
never a bad thing. Just because a
power supply is rated for 400W,
or maybe 600W, does not
aggravate that it is drawing that
at any given time. It just
indicates the total power
available to the various lines
inside the computer. For those
interested in getting a good idea
of their minimum power
requirements, this Power
Wattage Calculator is a
convenient reference. In addition
to checking out the total
wattage of a power supply,
looking for strong amperage
ratings on the 3.3V, 5V, and 12V
lines is also recommended, as
power supplies with identical
total power ratings may
distribute the power to the
various lines in different
quantities.
Power supplies come in a few
different physical sizes, but the
most common are designed to fit
the standard ATX and micro ATX
(mATX) form factor cases. A
typical ATX power supply, such as
this Echo-Star 680W unit,
measures 3.25 "x 6" x 5.5 "and
features two cooling fans to not
only cool the power supply, but
to also help draw hot air out of
the computer. typical mATX
power supply, such as this A-
Power 320W unit, measures 2.5
"x 5" x 4 "and due to the smaller
size features just one cooling fan.
mATX cases are generally much
smaller than ATX cases, and
therefore have smaller power
supplies, generally lower power
ratings, and fewer connectors.
The connectors on a power
supply also deserve
consideration. Most power
supplies come with what looks
to be an electric octopus of wires
hanging off the back surface, and
you need to make sure that
somewhere in that tangled
bundle are all of the connectors
you need. The power supply
should at least have as many
connections as the number of
drives, cooling fans, and other
items found in the case. Up until
recently power supplies had a
fixed number of connections, and
if you needed more, you needed
to use splitters to distribute the
power to all the components.
Modular power supplies, such as
the Ultra X-Connect 500W unit,
are now available that eliminate
that "electric octopus" all
together, and allow the end user
to connect just the cables they
need. The flexibility of a modular
power supply design not only
lets you customize the
connections to your needs, it also
makes for a simple and tidy
installation, since there are no
extra wires dangling inside the
case.
The selection of a high quality
power supply may cost more
money up front, but down the
road it could wind up saving
money. Many manufacturers now
offer power supplies that
consume less energy thanks to
high quality internal
components, advanced designs,
and active power factor
correction. These units are now
able to provide the same power
to the components in a
computer, but due to increased
efficiency, draw less power from
the electrical outlet.