Multiple 12v rails location question (modular psu)

[apcviewer]

I recently bought an Antec NeoPower 550 and it is also my first modular PSU so I am not sure how the 2 of the "3" 12v rails are divided. I am sure the hardwired 12v cpu cable uses one of the three rails. With a non modular PSU, it is hardwired so I never had to question it.

My question is, how are the remaining two 12v rails allocated? There are five modular outputs so would two outputs go through one rail and the other three outputs go through the other rail? If so, which outputs go to which rail? Or does the PSU somehow automatically allocate the modular outputs to a 12v rail?

 

[JonGerow]

NeoPower is actually a single rail PSU with a label that reflects three separate rails to appease the EM 60950 240VA safety requirement.

Don't sweat it.

 

[apcviewer]

Thanks for the input! That will make organizing wires easier on my part.

During my search for an answer, I have been reading various answers. None have directly mentioned to ignore the "muliple 12v rails" all together for the NeoPower (or other low to mid range psus). I did read that most psus with "multiple 12v rails" really only have one 12v rail, with each of the multiple rails supplying power to certain devices and that each of these "rails" can be overloaded. I didn't think the NeoPower would be one of those psus where I could completely ignore the "multiple rails." Thanks again!

 

[JonGerow]

Thanks for the input! That will make organizing wires easier on my part.

During my search for an answer, I have been reading various answers. None have directly mentioned to ignore the "muliple 12v rails" all together for the NeoPower (or other low to mid range psus).

That's because most PSU reviews don't discect the PSU to find out if the +12V rails are really split. At jonnyGURU.com, we did:

http://www.jonnyguru.com/modules.php?name=NDReviews&op=Story&reid=1 (True Power Trio is essentially a non-modular Neo Power)

http://www.jonnyguru.com/modules.php?name=NDReviews&op=Story&reid=21 (Corsair also uses Seasonic. Initially, their PSU's were sold as tri +12V rail, but now sell them as single +12V rail)

And you wouldn't "ignore" it for other low to mid range PSU's because most PSU's that claim to have split +12V rails really do split the +12V rails. It's really just the Seasonic built units that "fibbed" about having split +12V rails.

Of course, you could essentially "ignore" how the +12V rails are split because 9 out of 10 times when you have split +12V rails and a modular interface, either the modular interface is on one +12V rail by itself or different types of connectors are grouped in such a way to where one type of connector would not be on the same +12V rail as another.

Truth about multiple +12V rails: http://www.jonnyguru.com/forums/showthread.php?t=3990

I did read that most psus with "multiple 12v rails" really only have one 12v rail, with each of the multiple rails supplying power to certain devices and that each of these "rails" can be overloaded. I didn't think the NeoPower would be one of those psus where I could completely ignore the "multiple rails." Thanks again!

It's not one of those PSU's. The NeoPower simply doesn't have split +12V rails AT ALL.

Read the FAQ I linked above.

It is true that most multiple +12V rail PSU's have a single source, but that doesn't change the fact that in most cases each of these rails have an OCP (over current protection) that prevents more than a pre-determined amount of current to travel to the connectors on the rail.

In the case of the NeoPower and other Seasonic built units, the rail isn't split and there is no OCP. This is an exception and not the norm.

 

[apcviewer]

Thanks for the review links. I know next to nothing about psus so that TruePower Trio review helps me know a bit about the NeoPower (I rely on the manufacturer's information and by reading the review, I shouldn't put 100% faith on what the manufacturer shares). Before this, I was under the impression that the NeoPower actually had multiple rails with OCP. It was the FAQ that had me wanting to find the 12v rails and separate my video card from my hdd and optical drive. Thanks for your reply. It really clear up my questions, misconceptions and confusions.

A side note: The purchase of this psu was on a whim, to replace a cheap psu, so my information gathering about psus pretty much started then. Reading the review of the psu somehow made it easier to understand the FAQ.