power supply

Before You PC Power Supplies

Power supply units (PSUs) are often overlooked when building a computer system. A poor quality PSU can greatly reduce the life span of a good system or cause instability. A high quality PSU can also help reduce the noise or heat generated within a computer system. Whether you are buying one for a new computer or replacing a old unit, here are some tips for purchasing a PSU.

Avoid Power Supplies Under $30

           Most power supplies that are priced below $30 generally do not meet the power requirements of the latest processors. To make matters worse, the components used in them are of inferior quality and more likely to fail over time. While they may power the computer system, inconsistencies in the power to the components will tend to cause instability and damage to the computer.

ATX12V Compliant

Developments in processors, the PCI Express bus and graphics cards have all increased the amount of power required to operate them. To help provide this extra power, the new ATX12V standard was developed. The problem is that there are still a large number of older ATX power supplies available. Even if you are replacing an older power supply, ATX12V units are backwards compatible.

• ATX12V vs. ATX Power Supplies

Knowing the Wattage Ratings

Wattage ratings on power supplies can be deceptive as this is the total combined wattage of all the voltage lines. With the increased demands by components, the total required output particularly for the +12V line has become increasingly important. Ideally a power supply should have at least 18A on the +12V line. The actual load you need will vary depending upon your components.

• PC Power Supply Wattage

Low or No Noise

Power supplies generate a lot of noise from fans used to keep them from overheating. If you don't want a lot of noise, there are a number of options available. The best choice is for a unit that either uses larger fans that move more air through the unit at slower speeds or to get one with temperature controlled fans. Another option is fanless or silent power supplies that generate no noise.

• Silent PC Power Supplies

MTBF: Mean Time Between Failures

MTBF is the rating given by a manufacturer for the typical amount of usage a unit will have before a possible failure. Roughly 50% of units fail before this and 50% live longer. The higher the MTBF rating, the better the quality of the power supply. Avoid units with ratings of below 20,000 hours as this only equates out to roughly 2.25 years of continuous usage.

Power Efficiency

Power supplies convert voltages from wall outlets to lower levels used by the PC. During this conversion, some power is lost as heat. The efficiency level of the PC determines how much extra power must be put into the power supply to run the PC. By getting a more efficient power supply, you end up saving money through the use of less overall electrcity. Look for a unit that has the 80Plus logo showing that it has passed certification.