Buy A Good Power Supply

The power supply is one of the essential part in an electrical device that will affect the performance of your entire system. It's often the most undervalued, under-appreciated component within any device, yet one of the first components to cause failure.This post focuses on the factors to look for when purchasing a power supply for a personal computer.

1.Determine the wattage you need

Use a power supply calculator web page or software to help determine your requirements. Even better is to find a review of a similar system that measures power consumption. As that consumption is measured at the wall, multiply by the review system's power supplies efficiency to get the output. Don't purchase a power supply just above your requirements unless you plan not to upgrade the system. Purchase a power supply that will take you through your next few upgrades.

2.Research which connectors you need

Higher-end models may only provide a 24-pin connector, and lower-end models may provide just a 20-pin connector. Typically, most Pentium 4 and Athlon 64 CPU-based motherboards will require a 20-pin ATX connector, while newer motherboards require a 24-pin ATX connector. Also, most power supply will have both a 4-pin and 8-pin auxiliary 12V connector for motherboards, and only high-end power supply will have one or more 6-pin PCI-E connectors for video cards.

3.Look for power supply with high-efficiency ratings

And, ones rated under load temperatures, not room temperatures. Anything 80% and above is good. At 83%, approximately 17% of the wattage is lost as heat. Therefore, a power supply that may be advertised as a 500W power supply, will actually be drawing almost 600W at the wall. Efficiency drops over time and during the life of the power supply. A year-old power supply is most likely not capable of producing the same amount of energy it once did when it was new.

4.Determine the robustness of the power supply

How well does the power supply handle changes in current? Although not a guarantee, there's a strong correlation between weight and quality: bigger components equate to a more tolerant, reliable power supply. If you don't care about noise, an 80mm cooling fan in the traditional place on the rear of the power supply may offer better value.

5.Check the number of rails

Just as your house's fuse box includes both a large main breaker and a smaller circuit breaker per circuit to ensure the smaller-branch circuit wires do not overheat, high-capacity power supply divide their output into multiple "rails," each with a smaller current limit. The relevant safety standard requires a 20A limit, which is quite generous, given that the wires are smaller than those used in your house to carry 15A. A cheaper alternative is to provide just enough rails to total the overall capacity, which makes it difficult to use all of a power supply's capacity.

6.Get a modular power supply.

It will help eliminate extra wires to get in the way of cooling. Ignore the claims by PC Power & Cooling that modular cables create more resistance due to corrosion of contacts. The additional resistance is negligible. 

7.Compare the amperage of each voltage.

A power supply wattage rating isn't conducive to determining amperage at any specific voltage. All power supply will have a sticker with their rated amperage at each voltage level. This information should be provided when purchasing a power supply from an online vendor and visible on the unit's retail box.