I was looking around for some CPU benchmarks and happened to stumble across this piece of crap on what always used to be quite a good web site http://www.tomshardware.com/us/press/OCP-Power-Safety-26 I have reproduced the entire ad / article lest it be pulled.
Myth 3: A Single Rail Power Supply Is As Safe As A Multi Rail Power Supply! NO!
Single-rail power supplies do not come with the over current protection (OCP) safety function on their +12V rail. OCP limits the current that can go through the PSU’s rails into your PC when it exceeds a certain point, called the OCP set point. OCP is necessary because if you experience a short circuit in your system (which is unfortunately possible, even with modern equipment and building techniques) OCP will cause the power supply to shut off, preventing excessive levels of current from flowing into your system and damaging the hardware attached to it.
A single-rail power supply unfortunately does not provide this safety feature, due to its high current rails with up to 100A (100A x 12V = 1200 watts!). In the event of a short circuit or other failure of hardware, current flows unhindered into the system and damages everything in its path. If the user is unlucky and acts as grounding at that exact moment it could be even life-threatening. Are you really sure you want to install an unsafe power supply like this?
Myth 3: A Single Rail Power Supply Is As Safe As A Multi Rail Power Supply!
NO!
Single-rail power supplies do not come with the over current protection (OCP) safety function on their +12V rail. OCP limits the current that can go through the PSU’s rails into your PC when it exceeds a certain point, called the OCP set point. OCP is necessary because if you experience a short circuit in your system (which is unfortunately possible, even with modern equipment and building techniques) OCP will cause the power supply to shut off, preventing excessive levels of current from flowing into your system and damaging the hardware attached to it.
A single-rail power supply unfortunately does not provide this safety feature, due to its high current rails with up to 100A (100A x 12V = 1200 watts!). In the event of a short circuit or other failure of hardware, current flows unhindered into the system and damages everything in its path. If the user is unlucky and acts as grounding at that exact moment it could be even life-threatening. Are you really sure you want to install an unsafe power supply like this?
At Antec we deliver only high-quality power supplies and always make sure our customers are safe and can enjoy the hardware components they’ve purchased. So every multi-rail power supply we offer comes with the OCP safety function standard.
What a load of bollocks, there is absolutely nothing that is even close the being factual in this article, on top of that they play the fear factor and try to make you believe that you can be killed by a malfunctioning 12 volt rail !! And gee, imagine that, both diagrams have a SINGLE rail !! Shame Antec Shame, last time I EVER buy one of your products. Isn’t there laws against this type of reporting ?
But wait, it gets even better, in myth 2 they contradict themselves, don’ you just love it š From here myth 2a http://www.tomshardware.com/us/press/computer-power-supply-PSU-23 they say "In these early single-rail power supplies, a high level of graphics card power draw would overload the +12V rail, triggering overcurrent protection and causing shutdown" LOL !! remembering that in Myth 3 they say "Single-rail power supplies do not come with the over current protection (OCP) safety function on their +12V rail"
heres the article in case it is pulled !
Myth 2a: A Single-Rail Power Supply Is More Powerful Than A Multi Rail Power Supply!
Modern graphics cards make use of the +12V rail and it does not matter how many actual rails are being provided. Total power output, which is easy to find out, is much more important to graphics card compatibility than the number of rails.
The single-rail myth originates from a time not too long ago when a certain graphics chip manufacturer brought out a new chip requiring much more power from the +12V rail than the actual ATX norm allowed. The ATX specification clearly states 20A per +12V rail, but this was for safety purposes; in practice, the limitations of the 20A per rail specification might only occur with very demanding graphics cards. In order to exceed the 20A limit and power this new graphics chip, many companies overruled the ATX specification and built power supplies according to their own rules. In this way, the very first single rail +12V power supplies came to be. In these early single-rail power supplies, a high level of graphics card power draw would overload the +12V rail, triggering overcurrent protection and causing shutdown. So, many of these early models resolved this difficulty by simply omitting overcurrent protection. While these early models were not any more or less powerful on the whole than multi-rail PSUs of the same wattage, their ability to provide power past safe OCP limits on their single +12V rail created the erroneous impression that single-rail PSUs were somehow by definition more powerful. This is, of course, false.
When single- or multi rail power supplies have the same output rating, they have the same amount of combined +12V power – in this case, 744 watts. Whether it’s spread across one rail or four, the same amount of output is still provided.
A better way to determine whether a single- or multi-rail power supply is more powerful is simply to look at the label. Every power supply is limited by its total power output listed on a label attached to the side or the bottom of every power supply. On this label you can find the +12V ratings displayed in Amperes (A). The total power a power supply can deliver on the +12V rails is indicated on the label as ‘combined power’.