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How to use the capacity of the 4x +12V multi rails +12V capacity on a Gigabyte Superb E720 PSU?

I have a question about multi rail +12V capacity on a Gigabyte Superb E720 PSU with 4x +12V rails each with an 18A capacity. The Gigabyte PSU has 2x 6+2 Pin PCI- E 2.0 connectors and 4x 4-pin Molex connectors. Each +12V rails is listed with a Cable Color: +12V1 is Yellow/Blue, +12V2 is Yellow/White, +12V3 is Yellow and +12V4 is Yellow/Black. How is the 18A per rail distributed across the connectors? Each 2x 6+2 Pin PCI- E 2.0 connector can supply 18A? How about the other 2x 18A rails? Do they supply power thru the 4 Molex connectors? how? Thanks.
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More about capacity 12v multi rails 12v capacity gigabyte superb e720 psu
  1. There's not that much difference between single rail and multi rail PSUs. The whole current carrying capacity of the multi rail PSU is available even w/o all the +12V cables being connected. It basically boils down to what it will take to shut down the PSU as it gets loaded up. On a multi rail PSU, if one rail's current exceeds the rating for that printed circuit board 'trace', it will shut down the PSU. On a single rail PSU, there is no Over Current Protection (OCP) per trace; the current would have to exceed the single rail rating to shut down the PSU. Both PSUs still provide the same amount of power as needed.
    See this for a better explanation: http://www.overclock.net/t/761202/single-rail-vs-multi-rail-explained
  2. Thank u for the prompt reply clutchc. I read the link for Single Rail vs. Multi Rail *Explained* and I understand the OCP limit which in the case of my Gigabyte Superb E720 PSU would be 18A on any one of the connectors. I am still confused about the individual connector Watt capacity, specifically the 6+2 Pin PCI- E 2.0 connectors and 4-pin Molex connectors. If I have a GPU that requires 2x 6+2 Pin (or 1x 6+2 Pin and 1x 6 Pin), does that mean that my Gigabyte Superb E720 PSU can only deliver 18Ax12Vx2=432Watts? Also, if I use a 2x Mollex to 1x 6+2 Pin adapter and I connect 2x Molexes (from 2 different cables coming out of the PSU), does that mean now that this new 2x Mollex to 1x 6+2 Pin can deliver 18Ax12Vx2=432Watts and one of the other existing 6+2 Pin can deliver 18Ax12V=216Watts for a total power delivery to the GPU of 432Watts + 216Watts = 648 Watts. Thanks.
  3. Best answer
    The individual connector wattage capacity is usually somewhat less than (18A * 12V) * 4. The total +12V system wattage is usually listed on the nameplate listed somewhere. How the individual cables are wired as to the 4 rails is anybody's guess. You'd need a schematic of the PSU to find out.
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