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Five Tips for Choosing Power
Supplies
The power supply is the most
neglected component on the
computer. Most users will spend
a great deal of time choosing a
new processor, video card, and
motherboard, but when it comes
to the power supply must users
try to be cheap. Don’t be. By
not caring about your power
supply, you will be paying a
higher electricity bill and will
be putting your equipment at
risk.
Efficiency is the parameter that
measures how much a power supply
consumes for its own operation,
and it is expressed by the mean
of a percentage. This percentage
tells the difference between the
wattage the power supply is
delivering on its outputs and
the wattage it is pulling from
the power grid. For example, if
a given power supply has 80%
efficiency, this means that when
delivering 200W on its outputs
this power supply is actually
pulling 250W from the power grid
(80% of 250 W is 200W). This 50W
difference between the two is
the amount of power the power
supply consumes to operate and
it is completely wasted – but
you pay for it.
A power supply with higher
efficiency will consume less
power from the power grid to
produce the same wattage on its
outputs. If we replaced the
power supply above for a unit
with 90% efficiency, we would
now pull 222W from the power
grid, saving 28W compared to an
80%-efficiency unit. This way a
power supply with higher
efficiency will reduce your
electricity bill. This way you
should pick a power supply with
the highest efficiency your
pocketbook can handle.
We want basically five things in
a power supply:
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First, that it is an honest
product and can deliver the
wattage its label says it is
capable of. Unfortunately,
the average user can’t tell
this by just reading the
box. But in United States,
it’s becoming less and less
common to find power
supplies that can’t deliver
what is written on the box
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Second, the highest
efficiency possible, as
already explained
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The third thing we want is
that all outputs from the
power supply stay inside
their allowed values all the
times. If you have a power
supply that is for instance
delivering +13 V instead of
+12 V this will overload
your components and may lead
to computer crashes and even
burning components
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We also want the outputs
from the power supply to be
as “clean” as possible,
without electrical noise or
fluctuations (“ripple"")
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And finally we want the
power supply to have
protections, so it will shut
itself down if something
wrong happens, reducing the
risk of having your
components burn
(Gabriel Torres is the
editor-in-chief of
Hardware Secrets,
a leading technical website with
the goal of uncomplicating the
complicated when it comes to PC
hardware.) |
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