The connections

The fact that the currently offered 80-plus gold power supplies originate from the top series, can also be seen in the equipment. Except for the FSP model, all tested power supplies have modular cable management. Behind this bulky term is hidden the possibility to connect with a plug connection at the back of the power supply only the stripping, which is also really needed.


Equipment questions


Relevant differences between subjects are the number of SATA and Molex connectors provided for hard drives and fans. Corsair's power supply units are brilliant and the latter is the result of the eight additional (not shown in the table) connectors for case fans.


Beneficiary


On the other hand, the connections at FSP (6 times SATA, 4 times Molex) and Enermax (6 times SATA, 6 times Molex) at least for power users is somewhat poor. Other gimmicks such as mounting screws or cable ties are always taken with pleasure and are also supplied by almost all manufacturers.


Rail transport


The most important task of a PC power supply is to provide a constant output voltage as constant as possible. Under constant full load, no test subject had problems to comply with these requirements. The task becomes more difficult with a heavily changing load. In the last comparison test, not all test subjects were able to cope with this.


This time, however, there were no serious outliers. On a high level, Corsair, Seasonic and FSP power supplies were able to settle down slightly, while Antec and Enermax performed slightly worse.


While the question of the maximum power of the supply voltages 3.3 and 5 volts is rather trivial in practice, it is quite important at 12 volts. Anyone who is concerned with the details of the "Intel Power Supply Design Guide" was able to read up to the 2005 edition that no supply voltage could supply more than 240VA - with 12V the 20 amp

In the current issue of the design guide, on the other hand, reference is only made to the European standard EN 60950. This, in turn, limits the corresponding "TNV current sources with overcurrent protection devices" to 250VA - which corresponds to just under 21 amps at 12 volts.


This is not sufficient for the 12-volt current requirement of a modern PC. Accordingly, Intel has two separately secured 12-volt rails for mainboard and processor. The motherboard and its plug-in cards are operated from the 12V1 bus via the 24-pin mainboard connector.


The CPU receives its own "12V2" rail, which is connected to the 8-pin CPU connector. Each rail is separately protected with its own current limiter. Thus, the mainboard and CPU can now be just under 21 amperes without violating applicable regulations.


However, since powerful graphics cards show powerful currents, two rails are sometimes not sufficient. After all, a really fast gaming graphics card requires quite a bit of 20 amps under full stress. Thus at least one 12 volt rail is required, which is then referred to as "12V3". From 600 watts of power it is even common to add a fourth track ("12V4").


This is the whole matter, however, a bit confusing, especially since many power supply manufacturers already provide the 12V2 rail with a PCIe connector for graphics cards. However, if a high-performance graphics card and CPU have to share a track, it is quickly switched off. The computer crashed abruptly during heavy load - especially in 3D games.


Therefore, care must be taken to supply the graphics card with at least one dedicated 12 volt rail (e.g., 12V3 or 12V4). An exact study of the manual is unavoidable. After all, it was clear at each power supply of this test which PCIe connector belongs to which rail - if not always at first glance.


It does not really take most power supply manufacturers with the 21-Ampere limit. For example, the power sources supplied by Enquax and Enermax deliver up to 25 amperes per rail, while Antec has a whopping 40 amperes.