Power Supply Coefficient Rating

Can any one explain to me how the power coefficient is derived in the <A HREF="http://www6.tomshardware.com/howto/20021021/index.html" target="_new">THG comparision of 21 power supplies</A>? What factors determine if the power supply received a good, satisfactory, or adequate rating? It appears that the power supplies that received a "good" rating if it put much more power than the manufacturer specified. Does that make a power supply better than others that received a satisfactory rating? Before THG comparision guide, the average consumer could only go by the manufacture's ratings. Shouldn't a power supply be rated as "good" if it performs as the manufacturer claims?

Case in point is a comparision of Enermax and Antec power supplies. I am trying to decide between the two manufacturers for my next 430W power supply. Some posts claim that the Enermax are nothing special and Antec is the way to go. A comparision of specifications would suggest that Enermax is the way to go. I can only buy a power supply based on specs.

Here is my ultimate question. Isn't the average consumer better off buying a name brand power supply based on the manufacturer specifications rather than a power supply that has a reputation for ouputing more power than it is rated for? Perhaps there are reasons for a manufacturer under rating the power supply. In that case wouldn't Enermax be the way to go rather than Antec. Or are there other factors that I am over looking?
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  1. My first suggestion, if you haven't done this already, is to email David Stellmack or one of the other editors and writers of that article.

    As for where I can help is in selection. What are your system specs. I mean all of them. Most parts run off of the 3.3V and 5V lines.

    The Processor, Motherboard, System and other Fans, HDDs, CD and DVD draw off the 12V line. Most PSUs I have seen have a lot of Watts but most of the amperes (A) are on the 3.3V and 5V lines. They give 12A.

    My AMD XP2000+ draws ~12.6A off the 12V rail under regular operation.

    AMD XP200+ @ 1.733 = 38.8A Max @ 1.75V = 5.658A @ 12V
    DVD-ROM = 1.1A @ 12V
    3 HDDs = 3 x 2.0A @ 12V
    PSU Fan = 0.25A @ 12V
    System Fan = 0.25A @ 12V
    Case Fan = 0.25A @ 12V
    Processor Fan = 0.25A @ 12V

    Total = 13.758A (Max) @ 12V

    You need to have at least 15A for a modern system. The more units you add the more you will need.

    The motherboard and AGP card will also draw from the 3.3V line. 6A-10A normally.

    The motherboard, memory modules, HDDs, CD/DVD's, FDD, USB, keyboard, mouse, etc. will draw off the 5V rail. 15-25A @ 5V normally.

    So you see, the main things about picking a PSU is A) to choose a company that makes reliable products abd B) that the amperes are sufficient on the rails you need them on.

    <b><font color=red>Fredi</font color=red> <font color=red>Fredi</font color=red> He's our man! If he can't do it no one can!</b>
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