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When building a typical PC (or even our dream machine) we often overlook a very important key component, the power supply. Some hardware vendors take advantage of this opportunity by saving costs and often fail to include a power supply that is powerful enough for the needs of all the other hardware in the system. It’s a fact that power supplies can be a cause of many possible problems in a PC. Erratic behaviour in the operating system, unstable memory, an unstable CPU, issues with USB and Firewire devices, and random shutdowns are just a few examples.

With all the advances of modern technology and smaller components, you would think hat less power would be required. Generally this is not true. With higher CPU speeds, and more advanced graphics cards, the power requirements of even the average PC have increased. And with more power comes more heat. And with more heat comes the need for more cooling systems, which in turn use more power. It’s a viscous cycle! The standard video card which used to come with a simple heatsink to cool its processor now comes with a fan because the processor on the video card runs so hot, the a heatsink alone isn’t good enough. In addition to drawing the heat away from the devices, additional fans are required to draw cooler air in and heated air out. More fans require more power.

Years ago we could easily operate with a 120-180 watt power supply. By today’s standards, this is way below the levels a PC needs to function normally. Although it is called a power supply, it does not really produce power at all. Instead it transforms unfiltered high AC voltage to a regulated low DC voltage. This process by itself creates heat which is why all power supplies are equipped with fans themselves.

There are two methods to determining how much power you actually need. The first is to simply purchase the highest rated power supply you can afford (450-550W). The second, less costly method is by approximating the computing component’s use of wattage based on the table below:

A final factor in determining the kind of power supply you should select is future expansion. The best rule of thumb is to add 25% to take this into account.

In your experience, you may have had a power supply that has worked for many months or even years and then suddenly one day your system goes nuts. Here are some common power supply related failures you should look for:

1. Insufficient power supply – this is normally the case as you upgrade or add load to your system. Your system might work normally for quite some time until you adding peripherals and expansion cards.

2. Overheating – the efficiency of your power supply is degraded as the temperature goes up. This is even worse if you are operating above the normal room temperature.

3. Power surges or quality of AC power – We have discussed power surge protectors with our other tech tips. Also be aware of other appliances that can interfere with the AC power line.

4. Insufficient airflow – make sure you have ample space outside your power supply and inside the computer case. It needs both clear ventilation for air to flow through the power supply. Occasionally check for dust accumulation at its grill guard. A can of compressed air can usually remedy this problem easily.

We hope you’ve found this powerful (pardon the pun) tech tip useful!

Disclaimer - The Micro 2000 Tech Tip is a free service providing information only. While we use reasonable care to see that this information is correct, we do not guarantee it for accuracy, completeness or fitness for a particular purpose. Micro 2000, Inc. shall not be liable for damages of any kind in connection with the use or misuse of this information.