PC Power Supply Unit – Is it important ???


Short answer – YES

For the long answer read on ….

Ever wondered why a good quality computer power supply costs Rs.3000 and upwards whereas you can get a Cabinet+PSU for 1000 Rs. What is the difference ?

Cheap PSU does not include the the following to save costs

AC Filter and Transient Suppressor – This is a relatively simple string of capacitors and surge suppressors which protect the input side of PSU from noise and surges in the utility power. Many local and cheap PSUs omit this stage altogether to save cost.

Power Factor Correction – Power Factor Correction helps to reduce the reactive current in the upstream Utility/UPS systems. To give you an example for powering a 100W load with a PF of 0.5 you need a 200W Utility/UPS power, whereas if the PF was 1.0 you would require only 100W Utility/UPS capacity.

Protection Mechanisms – Good quality PSUs have additional circuitry which monitors output load and shutdown when the PSU capabilities are exceeded. Cheap PSUs does not have such protection mechanisms and causes catastrophic failure when PSU capabilities are exceeded often frying the computer components.

Low quality components

Capacitors – Capacitors are used in PSU circuits to filter the DC to remove the ripple. The ripple content in the DC voltages can cause malfunctioning and premature failure of electronic circuits. Cheap PSUs may not have sufficient ripple control hence significantly reducing the life of your computer components.

Active Components – Cheap PSUs often use low quality MOSFETs and Rectifier Bridges. Further they wont have sufficient safety margins which may cause faster degradation of electrical characteristics. This adversely affects the life of the PSU and may result in premature failure of the same.


Efficiency is the percentage of output power / input power. Since there are AC/DC conversions occurring in a PSU, there will be losses in these processes. A cheap PSU doesn’t care about the conversion losses and will have an efficiency typically in the range of 65-70%. That means if you have PC needs 200W power, a cheap PSU will draw 285W from mains input. The extra 85W is wasted as heat. A good PSU will have efficiency in the range of 80 to 85% where the loss is just 35W and thus less heat is generated in the PSU. Due to less wastage an efficient PSU lower your electricity bills, and also extends the life of the PSU components.

Some of the best PSUs you should consider :-

Seasonic S12-II 430W
Seasonic S12-II 520W
Corsair VX-450

Is it worth paying Rs.2000 extra for a good PSU ?

I would say YES. Questions and Comments are welcome

About Bobby P Rajan

I will be writing about tech stuff ranging from nostalgic to cutting edge. I like to work on generating maximum value from the tech stuff i own. I will also touch upon gadgets which are interesting at current price points.

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