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Thread: Is My 5V Rail To High?

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    Default Is My 5V Rail To High?

    Hi, I have a 5 year old seasonic X660. I've check my psu rails using multimeter digital. Right now, the 12V rail is 12.22 on idle 12.26 on load. And the 5V rail is 5.11 on idle, and on load is 5.20. I'm concerns about the 5V rail. Is it too high? Why is it that the 5V increased when there's a load, not decreased?

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    4.75-5.25 is the ATX spec so it's fine.

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    Quote Originally Posted by Roxxas View Post
    And the 5V rail is 5.11 on idle, and on load is 5.20.
    Where did you measure it? At the power supply end or the computer end?

    The supply may be compensating for voltage drops, i.e. using feedback (5.20 is only 4% high)
    Last edited by ashiekh; 09-18-2018 at 04:14 PM.

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    Quote Originally Posted by ashiekh View Post
    Where did you measure it? At the power supply end or the computer end?
    At power supply end. I connect the multimeter digital to molex cable rom the power supply.
    Quote Originally Posted by ashiekh View Post
    The supply may be compensating for voltage drops, i.e. using feedback (5.20 is only 4% high)
    The 5.20V is still acceptable right? So the power supply compensating voltage drop, by increased the voltage it when there's a load? Is this normal?

    If the voltage become to high, is there some kind protection from the power supply so not damage my other component? What is the power supply behavior when the protection kicks in?

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    Yes, as Tator Tot commented.

    How accurate is your multimeter? just wondering, and it would be interesting for you to measure at the motherboard end.

    I only ask out of inquisitiveness; all is fine.

    The Seasonic X660 has over-voltage protection; I imagine it shuts down for protection.

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    Quote Originally Posted by Roxxas View Post
    If the voltage become to high, is there some kind protection from the power supply so not damage my other component? What is the power supply behavior when the protection kicks in?
    The Seasonic X 660 uses the SITI PS223 chip for output protections, where OVP is typically set at 3.9V, 6.1V and 13.8V for the 3.3V, 5V and 12V rails respectively.

    This review found the voltage delivery between +0.2% to -0.9% on the 5V rail, when new. But your PSU isn't new.
    Last edited by Rexper; 09-19-2018 at 03:07 AM.

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    The ATX refer to outputs voltage +-5% from nominal like said.
    its mean you can be in 10% load regulation.
    reviewers normaly check Output Voltage Accuracy.
    Line regulation normally not (How the main voltage affects the psu).
    And load regulation that should not exceed 5%, I could't find that its written.
    In the 5V.
    voltage accuracy is 4% like mentioned.
    load regulation to what you measured 1.73% (it should be 100% load).
    Back in days before myth levels and so 3% for both considered very good.
    and 50% for ripple levels.
    http://www.micropowerdirect.com/PDF%...20Supplies.pdf

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    Quote Originally Posted by Rexper View Post
    This review found the voltage delivery between +0.2% to -0.9% on the 5V rail, when new. But your PSU isn't new.
    I imagine the review was for voltages at the end of the cable, not beginning, and who knows how accurate the OP's meter is.

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    Quote Originally Posted by ashiekh View Post
    Yes, as Tator Tot commented.
    Ahhh, thank you I'm relieved now
    Quote Originally Posted by ashiekh View Post
    How accurate is your multimeter? just wondering, and it would be interesting for you to measure at the motherboard end.
    It's not expensive multimeter digital that super accurate, but it's better than reading voltage through the software. I don't know how to test it at the motherboard end. Will it be more accurate?
    Quote Originally Posted by ashiekh View Post
    The Seasonic X660 has over-voltage protection; I imagine it shuts down for protection.
    Ok then, I don't have to worry about my other hardware

    Quote Originally Posted by Rexper View Post
    The Seasonic X 660 uses the SITI PS223 chip for output protections, where OVP is typically set at 3.9V, 6.1V and 13.8V for the 3.3V, 5V and 12V rails respectively.

    This review found the voltage delivery between +0.2% to -0.9% on the 5V rail, when new. But your PSU isn't new.
    Thank you for your information sir, it's very usefull

    Quote Originally Posted by none77 View Post
    The ATX refer to outputs voltage +-5% from nominal like said.
    its mean you can be in 10% load regulation.
    reviewers normaly check Output Voltage Accuracy.
    Line regulation normally not (How the main voltage affects the psu).
    And load regulation that should not exceed 5%, I could't find that its written.
    In the 5V.
    voltage accuracy is 4% like mentioned.
    load regulation to what you measured 1.73% (it should be 100% load).
    Back in days before myth levels and so 3% for both considered very good.
    and 50% for ripple levels.
    http://www.micropowerdirect.com/PDF%...20Supplies.pdf
    Thanks for your info, it's very knowledgeable

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    Quote Originally Posted by ashiekh View Post
    I imagine the review was for voltages at the end of the cable, not beginning, and who knows how accurate the OP's meter is.
    OP said they measured from the molex cable. That should be fine?

    If those voltages are true readings, they are fine for now. But I wouldn't expect them to stay in spec after another year or two.

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