Buying GuideComputer Tips

How to Buy a Computer Power Supply

The computer power supply is the Rodney Dangerfield of all the components that make up a computer. The computer power supply just doesn’t get any respect and its job is one of the most important of any component for your computer’s longevity and performance.

Specifically the computer power supply’s job is to convert the AC power supplied by your home into nice clean DC power for your computer.

What the Computer Power Supply Really Does

The computer power supply’s main job is to supply three different DC (direct current) voltages to the computer. These voltages are as follows.

  • +12VDC for motors and voltage regulators, newer processors
  • +5VDC for motherboard, voltage regulators, serial & parallel ports, PCI & AGP ports
  • +3.3VDC for the motherboard chipset, system memory, PCI & AGP cards

The computer power supply also regulates current and helps to cool your computer with its intake and exhaust fans. The direct current supplied by the power supply must also be free of noise, spikes and dips in voltage (brownouts).

Do not Buy a Cheap Computer Power Supply

If you are a good gamer, you might choose a good quality of a power supply a good computer power supply will run a series of checks before it allows the motherboard to turn on. If everything is ok it sends what is called a Power Good signal to the motherboard. Once the motherboard has received this signal it knows it is okay to boot up.

Cheap power supplies may not perform their internal checks before sending the all clear signal for the motherboard to power up. This can cause damage to the motherboard or other components in the computer because the proper voltages are not present at startup. and it can be a problem soon

Hopefully I am convincing you not to trust the cheap power supply that often comes with a case you might need  a little money to buy but it has good quality to start on.


Quick Guide for Computer Power Supply Wattage

Here’s a quick guide to determine the total average wattage of the different components the power supply will be supplying power for. Do the math and then add a 100 watts (just to be safe) and you’ve got an idea (ball park) of the total wattage needed for your computer.

Motherboard-, 15-30 watts

Low-End CPU-, 20-30 watts

Mid To High-End CPU-, 40-100 watts

RAM-, 7 watts per 128 MB

PCI Add-In Card-, 5 watts

Low To Mid-Range Graphics-, 20-60 watts

High-End Graphics-, 60-100 watts

IDE Hard Drive-, 10-30 watts

Optical Drives-, 10-25 watts


ATX Connector

The computer power supply is connected to the motherboard by a big white 20 pin connector. Recently this connector was changed from a 20 pin to a 24 pin. The new designation is the ATX 2.0 connector. Make sure you know which connector (20 or 24) is on your motherboard before buying a computer power supply. Also, be aware that PCI Express videocards have a connector that is not common on older PSUs (power supply units).


Cooling

 

All computer power supplys require some form of onboard cooling due to the heat they generate. The best type of onboard fan to have is a 12cm(diameter). These larger fans can push more air at slower speeds which results in less noise. This is a good thing. Smaller fans must spin faster to generate the same air flow and that leads to more noise.


Detachable Cables

Older computer power supplies had a certain number of power leads that emerge from the rear of the PSU. If you could use them all great, if not you had to find somewhere to tuck them. The newer computer power supplies have modular power cables that permit you to just use the power cables that you need. This is a good thing because it reduces clutter inside the computer case, which in turn increases the cooling efficiency of the fans.


Don’t settle for a low quality power supply. Make sure you buy a good quality computer power supply that is large enough to meet the computer’s power requirements and that it has the right power connectors to fit the motherboard that you have picked out.

Hopefully this article meets your needs and buy now and enjoy!


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