Power supply units are responsible for delivering power to individual
components within your PC. Few units offer their own surge protection,
and as many components are fairly delicate, it is always advisable to
plug your PC into the wall via a surge protection device of some sort.

Thankfully, power supply units are fairly reliable, and the majority
outlive the working life of the PC. However, with newer components
requiring more power than ever, typical supply ratings have increased
significantly in line with the demand. Unfortunately, this means more
heat, and whilst good quality supplies will still comfortably see your
PC through its lifespan, cheap supplies have become synonymous with
early failure.

When looking for a new or replacement power supply, there are a few
things to bear in mind. The first and foremost is the form factor, and
the most commonly used are ATX and the newer ATX-2. Older machines
still use the AT form factor, though these are becoming less common. To
confirm what you currently have, simply take the case off of your
machine and look for a sticker on the power supply, which should tell
you everything from form factor to rating in watts.

The next thing to consider is the rating, which is quoted in watts. It
is never advisable to go for a lower rating supply than you currently
have, as it simply may not be able to deliver enough power to all
components. In many cases, going above your current rating will be
beneficial, as it will be able to handle additional hardware, as well
as run at less than full capacity, hence lowering heat generation and
extending its lifetime. Typical supplies are around the 350-400 Watt
region, though it is not uncommon to come across supplies or 500 Watts
or more. If you have a new machine with an up to date graphics card and
multiple hard and optical drives, then you may be advised to go for a
higher rated supply of around 500 Watts, though older machines should
cope perfectly adequately with a 350 Watt supply.

You will also need to check that the supply you are looking at has the
appropriate connectors. Newer supplies may be quoted as being ATX12V
compliant, which means they are suitable for power hungry Intel Pentium
4 and AMD Athlon systems. These are compatible with older systems, as
this merely indicates that the supply has the additional 4-pin 12V
connector required on the aforementioned systems.

It is always worth noting what connectors are available. Most supplies
have adequate connectors for a hard drive, optical drive, floppy disk
and so forth, though if you have multiple drives as well as a new
graphics card, it may be worth looking for something with a little
higher rating. You can piggyback power connectors, but you shouldn�t do
this too much to avoid overloading the power supply.

Finally, always aim for as higher quality power supply as you can
afford. Cheap supplies are generally best avoided, and whilst you
needn�t spend an excessive amount, getting one from a reputable brand
will pay dividends in the long run. You may also wish to look at silent
power supplies, particularly if your machine is located in a quiet
environment, though again this will all add to the cost.

Power supply units are responsible for delivering power to individual
components within your PC. Few units offer their own surge protection,
and as many components are fairly delicate, it is always advisable to
plug your PC into the wall via a surge protection device of some sort.

Thankfully, power supply units are fairly reliable, and the majority
outlive the working life of the PC. However, with newer components
requiring more power than ever, typical supply ratings have increased
significantly in line with the demand. Unfortunately, this means more
heat, and whilst good quality supplies will still comfortably see your
PC through its lifespan, cheap supplies have become synonymous with
early failure.

When looking for a new or replacement power supply, there are a few
things to bear in mind. The first and foremost is the form factor, and
the most commonly used are ATX and the newer ATX-2. Older machines
still use the AT form factor, though these are becoming less common. To
confirm what you currently have, simply take the case off of your
machine and look for a sticker on the power supply, which should tell
you everything from form factor to rating in watts.

The next thing to consider is the rating, which is quoted in watts. It
is never advisable to go for a lower rating supply than you currently
have, as it simply may not be able to deliver enough power to all
components. In many cases, going above your current rating will be
beneficial, as it will be able to handle additional hardware, as well
as run at less than full capacity, hence lowering heat generation and
extending its lifetime. Typical supplies are around the 350-400 Watt
region, though it is not uncommon to come across supplies or 500 Watts
or more. If you have a new machine with an up to date graphics card and
multiple hard and optical drives, then you may be advised to go for a
higher rated supply of around 500 Watts, though older machines should
cope perfectly adequately with a 350 Watt supply.

You will also need to check that the supply you are looking at has the
appropriate connectors. Newer supplies may be quoted as being ATX12V
compliant, which means they are suitable for power hungry Intel Pentium
4 and AMD Athlon systems. These are compatible with older systems, as
this merely indicates that the supply has the additional 4-pin 12V
connector required on the aforementioned systems.

It is always worth noting what connectors are available. Most supplies
have adequate connectors for a hard drive, optical drive, floppy disk
and so forth, though if you have multiple drives as well as a new
graphics card, it may be worth looking for something with a little
higher rating. You can piggyback power connectors, but you shouldn�t do
this too much to avoid overloading the power supply.

Finally, always aim for as higher quality power supply as you can
afford. Cheap supplies are generally best avoided, and whilst you
needn�t spend an excessive amount, getting one from a reputable brand
will pay dividends in the long run. You may also wish to look at silent
power supplies, particularly if your machine is located in a quiet
environment, though again this will all add to the cost.