Many people do not realize that the computer power supply unit (PSU) is the most important part of a computer. It is like the human heart but instead of pumping blood it pumps electrons. The pc power supply unit is a component that you must search well before buying or else you may face some unpleasant surprises.
PC power supply is never advertised by the computer shops in their ready systems. They ignore the importance of the computer power supply unit and as a result, ignorant people ignore it too. Unfortunately, many people spend their money in experts because they cannot identify the problems from a faulty PSU.
As a newbie I had also such experiences. Many times I forced to send my computer to service for testing that lasted weeks. Many times I got my pc back intact because they could not find any problems on it. Problems coming from a faulty PSU are very nasty. I will write about them soon.
I believe that anyone who wants to buy a new computer must search for and buy a quality power supply unit. This is the purpose of this page and all of the sub pages; to help the beginner understand the importance of the pc power supply unit and how to buy a good product. Let’s see some basics about computer power supply units.
PSU Basics
First of all what a PSU is and what it does? The PSU is the hardware part that is responsible to power up the computer. It actually transforms the AC to DC. The PSU outputs specific voltage lines that are called rails. These voltage rails are like channels and every channel “works” at a specific voltage power.
As you search for the best pc power supply, looking at its specs you actually see its potential in every voltage rail. What it matters from the specs view is the total nominal power (measured in (W) Watts) and the maximum current (measured in (A) Amperes) in each voltage rail.
Every pc power supply provides the following voltage rails:
- +3.3V
- +5V
- +12V
- -12V
- +5Vsb
These Voltages are combined through the PSU’s cables. The cables connect with the internal computer parts and power them up.
A quality computer power supply unit provides stable voltage under every rail. The closer the real voltage values to the nominal, the better the PSU is. This is only identifiable by testing the PSU with a multimeter. This is the reason that you have to read reviews and benchmarks of a candidate PSU.
Maximum Load of the Voltage Rails
As we discussed above, the power of every rail is measured in Amperes. When you look at these specs you search for the higher numbers. You want your PSU to provide as many Amperes as possible to every rail but more importantly to 12V rails. Of course these are theoretical values and not the real ones. In reality things are different.
Do not rely only on the specs because the performance of a computer power supply unit depends on many factors. Only by testing a PSU you can see if its specs are close enough to reality. Hopefully there are plenty of websites that test and review the power supply units for you. It just needs a little time to read these reviews.
Let’s see now which steps you need to follow in order to buy the best pc power supply for your needs.
Buying a PC Power Supply Unit
The first thing you must determine is the total power of the PSU. The PSU must be the last component you search for. This is because you have to know what the other parts of the computer are and so to calculate how many Watts you need from the PSU.
There is a very helpful website that provides a free online PSU calculator. You can find it here http://extreme.outervision.com/psucalculator.jsp. When you decide your computer components, go there and see their power requirements. This tool will give you a first view of the nominal power that your PSU must have.
Add up at least 100 watts from the calculator’s result. This way you will be sure that your computer will have enough power. Also you can add or upgrade hardware at a later time without the fear of a power shortage.
The second step requires from you to check and compare PSU specs. As we already mentioned you have to look at the power of each voltage rail. The higher the numbers the better.
And finally you check computer power supply reviews for the models you selected from previous steps. You buy the one that the real values of the voltage rails are closer to the nominal. I must say here that buying a good PSU cost lots of money. Forget the cheap PSUs of $40 and $50. Usually a quality computer power supply unit cost over $100 and it is manufactured from a reputable company.
You must be generous when buying a PSU. The performance and most importantly the stability of your computer is highly dependent from the power supply unit.
Computer Power Supply Key Points
- Power supply unit is the most important part of your computer.
- The PSU takes the 220V AC and converts it to DC. It outputs several different voltage rails.
- Before buying a PSU you must be sure that its nominal power over-covers your computer’s needs. Use the PSU calculator.
- Select PSU models that provide the highest Amperage in every voltage rail.
- Check benchmark and reviews for the selected models and choose the one that has the smaller deviations between nominal and real spec values. This includes both Voltages and Amperes of every voltage rail.
- Do not expect to make economy by buying a cheap PSU. Quality products are expensive.
For more information about computer power supply units don’t forget to check also the Related Pages section on the left.
