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How to tell amps on a dual 12v rail psu

In my computer i have a 700w Raidmax RX-700AC Blackstone psu. im currently looking to upgrade the graphics. I was looking at a GTX570 which recommends a 38amp psu. my psu is a dual 12v rail design each with 23 amps. would i be able to run it. Do i combine the two rail amps to get the total amps. Thanks in advance.
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  1. I think this should be right

    [682W - (5V + 3.3V) * 25A] / 12V = 39.54A
  2. If each rail has 23 AMPS, make sure you use the 2 different PCI-E harnesses to plug into your card. ie not the daisy chain connectors, as they are obviously on the same rail.
  3. Best answer
    Raidmax Blackstone RX-700AC

    Total Output: 700W

    -12V: 6W
    +5VSB: 10W
    Max Combined +3.3V & +5V: 150W

    700W - 6W - 10W -150W = 534W

    534W / 12V = 44.5 Amps

    The Raidmax Blackstone RX-700AC's maximum combined +12 Volt current rating of 44.5 Amps should be enough to run a system with a single GeForce GTX 570 graphics card.
  4. Yeah but each 12V rail is limited to 23A, so it's important to use 2 separate rails for the Gfx card.
  5. Best answer selected by kpelton94.
  6. This topic has been closed by Mousemonkey
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