Newegg’s Power Supply Calculator is a online form that can be used to calculate a rough minimum power supply unit wattage. Many computer builders select a power supply unit that is over-dimensioned for the computer system that they are building. This is usually fueled by users on the Internet who give advice to pick a high-end power supply unit to be on the safe side.

The user has to enter data in the requested fields of the power supply calculator including information about the processor, video card, motherboard, computer memory, hard drives and optical drives. The calculator will then crunch some numbers and suggest a minimum wattage for the power supply unit.

It is always a good idea to pick a power supply unit that offers additional capacities to be on the safe side. This could be important when adding new computer hardware to the PC. It is therefor not advised to select a 400 Watt power supply unit of the calculator’s suggested wattage turned out to be 396 Watt.

There are obviously other factors that play a role like picking an energy efficient power supply unit (check out the 80 plus power supply units article for pointers).

Newegg’s Power Supply Calculator offers a quick calculation of the minimum wattage required for a specific computer system configuration. It is therefor a good starting point before selecting a power supply unit.

Companies began to research and produce energy efficient PC components that reduce the power consumption of a computer system without reducing its processing power. One of this programs is the 80 Plus initiative for power supply units. The power supply unit (or psu) is basically the unit that distributes the power to the various PC components by converting AC power from electric utilities into DC power.

Standard power supply units lose a lot of energy in that process while efficient ones lose considerably less. The 80 Plus initiative now certifies power supply units with a energy efficiency of 80% or more and a true power factor of 0.9 and more. This means that these power supply units need less energy to supply the computer system with the same power.

A desktop PC using an 80 Plus power supply will use 85 Kwh less per year than one with an average power supply unit. But this is not the only benefit. Those systems produce less heat which can mean a reduced noise level or reduced cooling costs. It also means that the PC components will usually last longer.

Not all power supply unit manufacturers are part of the 80 Plus initiative and it is possible to purchase efficient power supply units without the 80 Plus logo. The main benefit for the consumer is the immediate recognition that the psu is energy efficient. Someone would have to research the energy efficiency of a psu that is not included the program which could take a while and might even lead to no results.

80 Plus power supply units do not seem to cost more money than those without the logo which is why it is probably a good idea to pick one of those instead of regular ones on the next purchase. It should also be noted that there are actually four logos for 80 Plus power supply units which are standard, bronze, silver and gold with gold having the highest (7-10% above standard) energy efficiency.