What is a single rail gpu?

When we state "Single rail" it refers to the PSU not the GPU and is more correctly said as "Single 12v rail PSU".

You can tell by looking at the rating label.
A single rail PSU will read something like: 12V 50A
A multi rail PSU will read something like: 12V1 16A 12V2 16A 12V3 16A

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Thanks Hal,

So when you say it requires a single rail gpu you are saying in essence you need one 12V plug in from the psu rather than 0 or 2. Right?

Thanks Hal,

So when you say it requires a single rail gpu you are saying in essence you need one 12V plug in from the psu rather than 0 or 2. Right?

I'm not sure where you are getting "single rail gpu".
PCIe cards can have various combinations of 6-pin(75 watt) or 8-pin(150 watt) connectors. With the current PCIe specification allowing up to two 8-pin connectors on a card. If that is what you are referring to the connectors wouldn't really be called rails.

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the term single rail gpu is generally not used. usually what is mentioned are single rail psu and multi rail psu. so in my example there could be a single rail psu that does 100 amps. then there could be a multi rail psu that has three 33 amp rails that still add up to 100 amps.

let's say the video card you're using requires 28 amps to each of its two 8-pin power connectors. if you have the single rail psu you just plug it in and you're good to go.

if you have the multi rail gpu then you have to make certain that you don't put the two power connectors on the same rail otherwise the psu will overload.

Ok, now I get it. Juan mentioned it in building a new system post.

A rail! Just like my old choo-choo train that carried electricity thru the rails. :-)

Duh, again!

Thanks folks.

Ok, now I get it. Juan mentioned it in building a new system post.

A rail! Just like my old choo-choo train that carried electricity thru the rails. :-)

Duh, again!

Thanks folks.

Oh I see what you mean in their post. I think that was probably a typo. Given their the first part of their statement is about a PSU & the second part "be sure to buy a single rail GPU as posted by Wiggo." is probably referring to Wiggo's post just before mentioning a larger 12v rail for the PSU.

Things like that can really throw you off sometimes.

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Well I don't know about you but they can sure throw me off. I know my connectors are 12V something or other for gpu connections. Then we have 12v molex connectors for various things. We also have 100 watt bulbs. But trying to remember from HS physics about the difference in volts, amps and watts throws me after all these years.

I just looked up my psu pamphlet and it doesn't say anything about being a single or multiple rail. I just know I have gobs of cables and 'stuff'. I am still amazed after one year that I was able to put together my own PC without electrocuting me or my dog.

Well I don't know about you but they can sure throw me off. I know my connectors are 12V something or other for gpu connections. Then we have 12v molex connectors for various things. We also have 100 watt bulbs. But trying to remember from HS physics about the difference in volts, amps and watts throws me after all these years.

I just looked up my psu pamphlet and it doesn't say anything about being a single or multiple rail. I just know I have gobs of cables and 'stuff'. I am still amazed after one year that I was able to put together my own PC without electrocuting me or my dog.

I think for most computer things you would just need to remember these two out of the 12: V*I=W, W/V=I. For the AC side of things normally apparent power is good enough. With no need to calculate true or reactive power. Unless your power company charges you for your power factor, but most computer supplies are built to have a power factor near 1 these days anyway.

Sometimes the paperwork that comes with a PSU is very generic & may not have the ratings chart. There should be a sticker affixed to the PSU itself. Depending on how the PSU gets installed you may not be able to see the rating sticker. You can probably also look up the information on the PSU manufactures website. That is more often the route I go since it is less work than removing the side of the case to see if I can even see the rating sticker.

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Thanks Hal

Yes was a type error, my sugestion was to use a single rail PSU (not gpu as typed).

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thanks juan