Having a power supply which can deliver sufficient levels of amperage, voltage, and clean power is absolutely critical. The wattage of a power supply (PSU) is often touted as being the most significant part of a power supply. It is in fact not. The total amperage and the form compliance are more important. You want a PSU that deliver maximum amount of amperage. The 12V line is what supplies the processor and video card with power. These are the most power hungry components and thus makes the +12V line the most important part of a power supply.
One way to determine how much power a power supply can actually supply is to multiply the rated amperage on the 12V line by 12. For example, a PSU with 30 Amps on the 12V line can deliver 360 Watts of power. Of course, how many Amps the power supply can deliver is dependent upon many things like temperature and the quality of the capacitors.
Most computer will never exceed 30-35 Amps of power on 12V line. SLI systems with quad core processors and multiple hard drives rarely exceed 400 Watts of power (or about 34 Amps on the 12V line)
Some power supplies split their 12V line into different rails. Each rail is capable of supplying no more than 20Amps of power. However, a multiple rail line is not as good as a single rail line. This is because if you do not use all of the available amperage on one rail, it becomes wasted.
For Example:
You have a PSU will 2 â 20Amp +12V lines. You have a CPU and video card connected to the two individual +12V lines. The CPU is only using 8Amps while the video card is drawing 19Amps.
Guess what, the 1st 12V line that is connect to the CPU has wasted 12Amps because the CPU just doesnât need all of the power. While the first +12V is supply more than ample power to the CPU, the 2nd 12V line is barely able to give the video card enough.
Therefore, a system with a single high amperage 12V rail will out-perform its multi-rail cousin.
The amount of wattage is also important. However, if you ensure that the power supply you have is carrying sufficient amperage, it will also have enough wattage.
Sve je ovo u domenu teorije, a sad malo prakticno. Dual rail napajanje treba (mora) imati odvojena dva namotaja iz transformatora, odvojene ispravljacke (shotky) diode sa odvojenim filterskim kalemovima i odvojenim elektrolitskim kondenzatorima. Tako nesto ja nisam video vec se svodi na isti namotaj, istu diodu, isti filterki kalem i iste elektrolite, najcesce u grani 12V samo jedan. Konkretan slucaj je Codegen 550,650W. Svi su radjeni na istoj stampanoj ploci i svi su apsolutno jednaki. Jedan elektrolit ma kolikog kapaciteta bio jednostavno je nedovoljan za tako veliku struju. Pre ili kasnije njegov ESR ce se povecati tako da ce napon postati testerasti sa maksimalnim vrednostima koje daleko premasuju 12V i onda na red dolazi naduvavanje elektrolita na ploci koji su jako osetljivi na povisen napon i onda ako to potraje isti ce procureti. Ovde sigurno ima mnogo korisnika kojima se to desilo. Dakle jedini pametan zakljucak je da se na napajanju NIKAD ne stedi a stvarnost je da se na napajanju uvek stedi. I na kraju da dodam kod napajanja nikada nije problem u diodama jer ima dioda koje mogu da izdrze trajnu struju 20,30,40,60 Ampera a na nekim ispravljacima postoji mogucnost paralelnog povezivanja cime se duplira snaga (zamislite 2 x 60A = 120A x 12V = 1440W) medjutim cak iako bi trafo to izdrzao (debljina zice) koliko elektrolita je potrebno da bi izdrzali toliku udarnu struju ako recimo Rubycon MBZ serija 2200uF ima deklarisanu ripple current (udarnu struju) 2800mA (2.8A). Da li je neko u bilo kom napajanju video vise od dva elektrolita u grani za 12V?
Izvinjavam se ako je ovo bilo predugacko ili zamorno nekome.
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