Multiple Rails & Single Rails 12V

[Rickster]

I've been reading and it seems that there are advantages and disadvantages between using a multiple rail (2 or more 12V rails) and a single rail. Correct and add on if I'm wrong but basically:

1) manufacturers find it more expensive to build PSUs with high single rails than building multiple rails to obtain a higher Amps in the 12V rail.

2) using a multiple rail will not allow the main 12V rail to be disturbed by other devices like moving hardware devices like pumps, hard disks and also flickering lights. An advantage of the multiple rail.

3) a single high Amperage rail is better than a multiple rail with the same total Amperage. i.e. Single rail 12V = 38A. Multiple rail 12V1 = 20A and 12V2 = 18A.Purely because if your CPU all of a sudden requires more Amps from the 12V rail the single rail can still deliver it since the Amps are higher than a multiple rail.

So which is actually better? Is there a best of both worlds? Why do people still prefer single rails. If we can get a PSU that is multiple railed 12V and delivering high Amps on the 12V that supports the CPU and motherboard wouldn't that be better than the single rail?

Someone ought to write a sticky about this.

[Gautam]

If we can get a PSU that is multiple railed 12V and delivering high Amps on the 12V that supports the CPU and motherboard wouldn't that be better than the single rail?
In short...yes. Just that there are very few such PSU's. The majority of the more affordable high quality PSU's happen to be single rail. Multi rail PSUs in the same price range usually have comparatively weaker rails.

Not all multi rail PSU's are bad. The Silverstone ST65ZF and ST75ZF are each quad rail and are great. I had a dual rail Fortron 550 which was also very strong. I think its more a matter of selection and the current offerings. From what we've got to choose from right now, as I said, most of the best PSU's are single rail.

Best of both worlds? A dual 50A +12v PSU maybe? :D Lemme know if you find one. :p

[jivetrky]

In short...yes. Just that there are very few such PSU's. The majority of the more affordable high quality PSU's happen to be single rail. Multi rail PSUs in the same price range usually have comparatively weaker rails.

Not all multi rail PSU's are bad. The Silverstone ST65ZF and ST75ZF are each quad rail and are great. I had a dual rail Fortron 550 which was also very strong. I think its more a matter of selection and the current offerings. From what we've got to choose from right now, as I said, most of the best PSU's are single rail.

Best of both worlds? A dual 50A +12v PSU maybe? :D Lemme know if you find one. :p

I believe they give those out free when you buy a new in home nuclear reactor :)

[Rickster]

But as far as I know there are some PSUs that have no OCP. So technically it kind of makes it a single rail although there is multiple rails.