a. The more fan, the better?
Fans are relied upon to effectively disperse the waste heat generated by the power supply. In addition to the commonly seen single fan power supplies, power supplies with a double or even triple fan design for even better heat convection and concurrent dispersion of heat inside the computer have emerged on the market. Although in theory better dissipation efficiency can be attained with a larger number of fans, a good case design can actually also successfully dissipate waste heat. In single fan products, the fan is positioned either at the bottom of the power supply or the back of the power supply. A large number of fans may generate excessive noise, which is why single fan power supplies have gradually become the mainstream product. Therefore, the key is not the number of fans, but the heat dissipation efficiency.
b. The larger the fins, the better?
When opening the case of a power supply, the first thing that you will notice is the heat sink fins. Although the design concept used in many products is based on the theory that the larger the fins are, the better the heat dissipation will be, this theory does not necessarily apply to power supplies. In power supplies, the main function of the fins is to transform energy lost in the power transformation and output process into waste heat, and conduct this along the fins for dissipation. In other words, this waste heat is actually energy that is lost during operation of the power supply. The size of the fins should therefore be interrelated to the “efficiency” of the power supply. High-efficiency power supplies can adequately use and transform power, and thus generate a relatively small amount of waste heat, making it unnecessary to equip them with large fins. Besides, consumers who have studied fins probably know that rather than fin size, the fins’ “dissipation area” is what’s important when evaluating the dissipation efficiency, because the larger the dissipation area is, the greater the dissipation efficiency will be. Another key factor for the dissipation efficiency is whether the fins have a single-piece design.
c. Power Factor Correction (PFC) makes power supply more environmentally-friendly
In order to comply with the European EN61000-3-2 and IEC1000-3-2 standard for electrical equipment, the design of power supplies meant for export to Europe includes a PFC (Power Factor Correction) Circuit which reduces the difference between effective power (input AC) and apparent power (power consumption) and thus minimizes wasted energy. This way power can be saved and the goal of producing an environmentally friendly product achieved, while at the same time consumers are enabled to economize on their electricity bill.
There are two types of PFC circuits, namely active PFC and passive PFC. Passive PFCs mostly have a big choke (inductor), while active PFCs are equipped with a controller chip.
d. Others special designs
Today’s power supplies have many ergonomic and consumer-considerate designs. Fanless power supplies, for example, enable the user to find a balance between heat dissipation and noise, while with the fully automatic voltage setting of many power supplies users no longer need to worry about using the correct voltage when abroad. Other power supplies have focused on modular cabling, using better materials, coated anti-interference power cords, or wires of various lengths for easy planning and management. Serial-ATA and PCI-e power connectors are the main trend of today and the future. When purchasing a power supply, these are all design characteristics that consumers can take into consideration.
e. Weight is definitely not the decisive factor
The weight of components is definitely no longer a factor in deciding upon the quality of a power supply. Good quality power supplies are those power supplies that have a proper design and that comply with the relevant norms and standards. The method that was used in the past to determine the quality, comparing weight, can only be considered as unfair. Of course, standard-compliant power supplies are usually not that light. Users who have once used an inferior brand power supply that came with the computer case probably understand what is important.
On the market most power supplies are sold together with a computer case. To reduce costs, a good computer case is not necessarily paired with a good power supply, and we therefore strongly advise to purchase a computer case and power supply separately.