Need Help regarding power supply

[hhumas]

I have Delta 750watts psu and its sticker shows that it has 4 rails of +12v and each gives 18amps so 18amps x 4 12v rails =72amps
so is it possible that 750watts DELTA can give 72amps on 4 12vrails.....

 

[newtekie1]

I have Delta 750watts psu and its sticker shows that it has 4 rails of +12v and each gives 18amps so 18amps x 4 12v rails =72amps
so is it possible that 750watts DELTA can give 72amps on 4 12vrails.....

No, it isn't. Each rail can give up to 18 amps, but their combined power is still limited.

What model is it exactly?

Usually the sticker will also tell you the maximum combined power on the 12v rails. For example:

A quick rundown of how almost all modern "multiple rails" PSUs work. The first shocker, they are actually single rail PSUs. Take for example the 750w PSU from the picture I posted. It says the maximum combined 12v power is 700w, which is 58A. So that PSU actually has a single 58A 12v rail. They then take that single 58A rail, and split it in 4 circuits which they call rails. But really it is just like taking a single wire and twisting 4 other wires on the end of it, each of the 4 wires can still provide the same power as the original single wire, but combined they can't go beyond what the single wire can provide. Now each of the 4 "rails" is connected to a Over Current Protection circuit, that is set to 18A. This makes it so that if any one of the "rails" goes over 18A of power draw, the Over Current Protection kicks in and turns off the PSU. This is only a safety feature, to prevent shorts from killing the PSU and other parts of the computer, and possible starting a fire. This is really the only reason to do it. So now you've got 4 "rails" that can pull up to 18A each, but they are still limited by the initial 58A single rail they are all pulling from.

 

[hhumas]

http://www.delta.com.tw/product/ps/sps/sps_product.asp?pcid=4&ptid=1

 

[newtekie1]

http://www.nvgamers.com/attachments/f35/780d1322377409-need-help-untitled.jpg

The maximum combine 12v power on that PSU is 648w, so 54A.

 

[Jetster]

Im no expert but I like to try to understand. I get one single rail 700W 58A. Divided into 4 circuits limited to 18A each. Now of course if you could hook up all 4 to a single GPU it could provide 58A. But you cant right. There is PCI-e slot, and two 6 pins connectors. So if its only lets say two circuits that run the GPU then your limited to 36A right? Or is my logic flawed

 

[newtekie1]

Im no expert but I like to try to understand. I get one single rail 700W 58A. Divided into 4 circuits limited to 18A each. Now of course if you could hook up all 4 to a single GPU it could provide 58A. But you cant right. There is PCI-e slot, and two 6 pins connectors. So if its only lets say two circuits that run the GPU then your limited to 36A right? Or is my logic flawed

Yes, on the PSU side you would be limitted to 36A. Of course, the PCI-E slot and two 6-pins limits you to 18.75A, so you could really get away with that configuration on a single 18A circuit.