I’ve heard of rails, how many do I need?
Now this is a proper marketing war, over a simple difference in design.
Overall, units with multiple 12V rails are considered to be ‘safer’, while units with a single large 12V line are preferred by enthusiasts because they negate the possibility of a weak 12V line getting overloaded by a single power hungry device.
Let’s say this nice and clearly, to avoid misunderstanding… High-end PSUs, from quality vendors, that use multiple 12v lines – are created in such a way that all of these lines exceed the ATX safety specifications.
Units with single and very powerful 12V lines are [said to be – Ed] dangerous, because people try to imagine a catastrophic event which might force most of the power in the circuit being channelled through a single connector, in which case the cable would surely melt – possibly even starting a fire. The example normally quoted is when a faulty component doesn’t cause a short circuit. Quality manufacturers integrate several safety methods to ensure this does not happen, which is why such catastrophic events are extremely rare (although there is an interesting story about a French journalist who ended up in hospital while testing a ‘famous brand’ PSU – or so the story goes).

copied from kitguru

hmm any truth to it?? just curious