ATX Power Supplies Wattage

ATX Power Supplies Wattage

Desktop PC’s all come with an internal power supply unit. This unit has been dubbed the PSU for short. The PSU brings the power in from the electric socket through a cable connected to the PSU. In turn the PSU has a set of wires internally that are spread around the inside of the PC desktop casing which inside this case are all your PC components.

Desktop PC components can be your hard drive, CD-ROM, video card and these all need connecting to the PSU via the wires leading out of the PSU into the desktop casing. The PC components need to connect to the PSU so they can feed off the PSU’s distributed power which is being pulled through it from the electrical mains.

The PSU controls the amount of power being transmitted into each device and it is at this point the correct wattage becomes essential to avoid any electrical short circuits rendering components unusable or in layman’s terms fried!

ATX power supplies wattage come in two specifications

The two aspects to consider with ATX power supplies wattage are output peak and the maximum wattage output. These pose more questions and some confusion and really do need explaining to understand the ATX power supplies wattage.

ATX power supplies wattage peak output

This is maximum level of power that can be supplied by the PSU. This can only be supplied for a limited amount of time and will eventually drop off or the PSU will simply meltdown.

ATX power supplies wattage maximum output

This is the most important spec to look out for as it indicates how much power can consistently be supplied at a safe level. The main factor here is as with most electrical wattage considerations you need to ensure that your ATX power supplies wattage maximum output is above the amount you intend to use. This not only allows additions to be added on, but also ensures there are no meltdowns. In fact the components should not be able to reach this level if you have chosen wisely.

Levels of voltage output and calculating maximum output

The three main levels in a PSU are 12V, 5V and 3.3V which are used to supply the different PC peripherals with the necessary voltage levels. To get a feel for the ATX wattage you require you should add all the components combined energy consumption.

  • To calculate this means you use a simple equation: AMPS x Voltage = Wattage

To get an idea of how this works a typical 12V line with an 18A supply means there are 216W of maximum output available. On top of this you need to also calculate the additional 5V and 3.3V.

A final note is in regards to the 12V rail on the PSU that supplies all the desktop hardware requiring 12V of power. This puts the most power pressure on your machine supplying hardware components usually attached to the motherboard. Make sure this is taken fully into consideration.

When calculating the ATX power supplies wattage think about what you are using your machine for. Sometimes power usage will be low, but then when you play intense graphical games for long periods of time other components will start to suck more power. As a rule of thumb always calculate the maximum output well above the actual combined components required wattage.