A Complete Guide You Must Read Before Buying A Power Supply Unit

Choosing a power supply for PC is a serious task. It may be more difficult than what you may think. There is a common power supply to all the components of your PC. If you use any unrated power supply to power your PC, these components can get damaged with prolonged use. Heating problems arising in the PC are common to situations where people have used an unmatched power supply.

Here we discuss all the tips which you should consider before buying and PSU or the Power Supply unit for your PC.

Calculate the Wattage accurately

Take a sum of the wattage of the individual components of your PC to know the real wattage required. But your job does not stop here. Take a 20 percent higher value, than you have calculated. This higher wattage value will account for any power shocks, keep it as a buffer. With the advancement in technology, PC parts are becoming more and more efficient by the day. You should also keep a suitable buffer for any future enhancements you might want to do on your PC. Do not forget to add you speakers to the calculations.

Then calculate the big guy, Ampere

Simply put, Ampere is the most important value you should look out for. Even with a slight rise in ampere value, your PC can become hot as the sun. To calculate the ampere rating you can use this formula: Power (Watt) = Voltage (Volts) X Current (Ampere).

To give you an example, if the total ampere that is required by your PC adds up to 30A, working it at 12V would mean a wattage of 30X12=360 Watt. Now you need to take a number 20 percent higher than the calculated value for the PSU. Here, in this case, the power rating required for the PC would be 432Watt.

Price of the Power Supply Unit

Expensive does not always mean the best. You should strike a balance between the cost and the usage of your PSU. As a general calculation, the cost of the PSU should be within 10-20% of the overall cost of the system. For example, If your whole system cost calculates to 1000$, then you should set aside money from 10% (100$) to 20% (200$) to buy your power supply unit.

Efficiency of the PSU

The more efficient a PSU, the less it will cost on your power bill. Also, a more efficient PSU will make less noise, giving you less noise pollution. Efficiency means that maximum input which is given into the PSU is converted to as output. Therefore, it will reduce your power usage and can have a long-term cost effect. PSU are rated on efficiency parameters by a standard called 80 PLUS.

The order of efficiency in this standard are:
1) 80 PLUS.
2) 80 PLUS Bronze.
3) 80 PLUS Silver.
4) 80 PLUS Gold.
5) 80 PLUS Platinum.
Platinum signifies the most efficient ratings.


Always keep in mind these tips before you choose your PSU. Don’t just look at the initial cost of the product, but also calculate its long-term cost. The power rating, efficiency and the certifications are necessary to ensure that you have purchased a quality product.