PC Power Supply Requirements
Tips on Selecting PC Power Supplies

PC power supply requirements aren't hard to understand. Faster computers require more power.

The PC power supply is encased in a hard, sturdy box that is sealed and holds AC-to-DC power conversion hardware.

Power supplies provides electricity to run the electronic components in the computer. The power supply is essentially what allows a computer to run. Without it you couldn't turn on your computer, so of course it is mission critical.

The power supply is in a metal box ... sealed ... usually includes at least 1 cooling fan, and holds the hardware for AC/DC power conversion.


It provides electrical power to the key components in the computer, and is located inside the PC case in the corner. You will be able to see it from the back of most computers because the fan grid is quite easy to see.

Power supplies, a/k/a "switching power supplies", contain switcher technology which converts the AC input to lower DC voltages.

The computer power supply, once connected properly, allows you to turn on your computer with a power up button that is located on the front of the case.

Some keyboards also offer a power up/power down button for the computer. This is really convenient because it means you don’t have to reach to turn the computer on; the button is within a finger stretch!

Things you need to consider:

If you buy a second hand case watch out. Older cases may not have a power supply powerful enough to drive the latest CPUs.

When you have the option to select the power supply, check for reliability ratings or user reviews. I suggest that you look for power supplies that are also certified by UL, CB, CE, TUV and FCC.

You need to know what kind of warranty is offered;12 months is the minimum to know you are getting a good quality power supply.

Don't touch power supplies of 250 watts or less! When building a new state-of-the-art system, you need to look at units that are 300 watts or more.

Know what the power requirements are for the hardware you have installed or will install in your computer, check out these wattage requirements for the common computer parts:

• Motherboard 15-30 watts
• Low-end CPU 20-50 watts
• Mid to high range CPU 40-100 watts
• RAM 7 watts per 128MB
• PCI add-in card 5 watts
• Low to mid level graphics card 20-60 watts
• High-End graphics card 60-100 watts
• IDE hard drive 10-30 watts
• Optical drives 10-25 watts

You should add up your estimated requirements, add another 30% or so for safety and upgrades to get a rough idea of your minimum requirement. You should always go more than the minimum.

If you are into top of the line, heavy graphics, overclocking, bells and whistles, start with a 400 watt power supply at least.

Pay attention to the amount of stuff you have plugged into the same electric circuit as your computer. Don't overload the circuit. Don't plug things with high wattage requirements, such as heaters, electronics, etc. into the same circuit with your PC.

Remember that the price of a good power supply is small when compared to the cost of all the parts of your PCr. Do consider quality when you shop for that new case or power supply.

Check out popular power supply hardware and the latest deals on them at TigerDirect



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