The power supplyo PSU it is one of the fundamental components of a Desktop PC, despite being often underestimated. By bringing voltage to the whole system, it is important that the power supply is of good quality and above all that it is as efficient as possible: so the whole PC will consume less and there will be a net saving. In this regard, the 80 PLUS certification, but what is it about?
A quality power supply is essential for your Desktop PC
Why is efficiency so important? It is the ratio between the input and output power. If, for example, your power supply supplies 500W to the PC but draws 625W from the wall socket, the ratio will be 500/625 = 0,8, so it will have 80% efficiency. Those 125Ws are nothing more than produced heat. A power supply can be said to be efficient when it produces little heat and has low energy consumption. An efficient PSU will cost more than a cheap power supply, but will save over time by consuming less power.
The program was born in 2004 to evaluate the efficiency of the power supplies 80 PLUS which, on a voluntary basis (no manufacturer is obliged to certify the power supplies), indicates which products are with a minimum efficiency of 80%. The efficiency is measured with an input of 115V and 230V, at different loads: usually the maximum value is reached when the PC uses 50% of the total load of the power supply. The birth of the 80 PLUS program, despite having some defects, has made it possible to realize the importance of a good quality power supply.
there 6 levels certification: 80 PLUS, 80 PLUS Bronze, 80 PLUS Silver, 80 PLUS Gold, 80 PLUS Platinum and 80 PLUS Titanium. They range from an efficiency of 80% up to the Titanium level with a maximum of 96%.
Currently the most popular levels are 80 PLUS Bronze e Gold, as they have the best efficiency / price ratio.
But it's not all plain sailing. Unfortunately, this certification has some flaws, such as the lack of rigidity in the controls, which allows manufacturers - hypothetically - to have a power supply certified "built ad hoc" to have a percentage of efficiency different from the model actually marketed. Furthermore the tests do not measure power consumption in standby mode, which is very important if European standards are to be respected. According to the ErP / EuP guidelines, a standby power supply should consume less than 1 watt.
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Cooler Master Masterwatt 650W: semi modular, efficient and silent
Among the best known models we find the Cooler Master Masterwatt 650W with 80 PLUS Bronze certification, which we have had the opportunity to test for a long time. His average efficiency is 85% with peaks up to 88%. But efficiency is not everything for a power supply. In fact, before choosing the right model, other characteristics are also evaluated such as noise, type (for example semi-modular or modular) and power.
In addition to producing little heat and therefore allowing lower energy consumption, this power supply is defined semi-fanless. In fact, under 15% of the load the fans will not spin, as a result we will have a really quiet PC. As the required energy increases, the fans gradually increase speed and noise, but remain always below 30db.
The Masterwatt 650W is a power supply semi-modular, it means that the 24 pin ATX cable (the “big” one that powers the motherboard) and the EPS 4 + 4 cable (to power the CPU) are fixed, while the rest of the cables are modular. Then you can insert the various cables for the peripherals according to your needs. Compared to non-modular power supplies, this allows you to manage fewer cables and therefore have a cleaner PC from the point of view of cable management. It differs from modular power supplies because it has two fixed cables.
Buy it or not?
This power supply is a great product, built with the quality that Cooler Master has accustomed us to. There 80 PLUS Bronze certification allows you to have a good level of efficiency, while maintaining a limited budget. Obviously in case you are looking for the top in terms of efficiency, our advice is to aim for a Gold certified PC power supply. For mainstream users looking for a product stable, quiet and reliable, this is the right choice. Cooler Master offers different wattages in addition to the model tested by us, such as 550W and 750W. To find out which one is right for you, you can calculate the energy consumption of your system by visiting this site. Just insert all the components to be powered and that's it!
Cooler Master Masterwatt 650W
For 
- silent
- Semi-modular
- 80 PLUS Bronze certification
Cons 
- You may want to aim for a higher certification based on your needs
