Help a newb connect his power supply cables to the motherboard?

Discussion in 'hardware' started by paulescobar, Mar 22, 2015.

  1. paulescobar

    paulescobar Registered Member

    Joined:
    Sep 22, 2008
    Posts:
    181
    My Background

    I am mostly a software kind of guy, and this is my first time building a computer. I saved lots of money, did lots of research, and picked my parts.

    So far, I've installed my CPU & Fan to the Motherboard, and mounted them to the case.

    Now it's time to install my Power Supply. Mounting it to the case is easy. The problem comes when I have to connect the cables. The manuals don't explain the purpose of these cables or provide "step-by-step" instructions.

    I've been searching for over an hour, but can't get a clear idea of what I'm supposed to do. So I'm hoping someone can help me here.

    Hardware

    Motherboard: MSI Z97 XPOWER AC
    Motherboard Manual:
    Code:
    http://ca.msi.com/support/mb/Z97_XPOWER_AC.html#down-manual
    Power Supply: Seasonic X-1250
    Power Supply Manual:
    Code:
    http://www.seasonicusa.com/images/BrochureManuals/New_X_Manual.pdf
    Problem

    On page 29 of my Motherboard manual, it shows 4 different power connection slots (JPWR1, JPWR2, JPWR3, JPWR4). Unfortunately, it doesn't explain what goes in them.

    On page 59 & 61 of my Power Supply manual, there is listing of all the key cables.

    I think the "Mainboard 24/20 Pin" cable goes into the "JPWR1" slot.
    - So I am mostly confused about the other slots (JPWR2, JPWR3, JPWR4).
    - Also, it's confusing that there are two CPU cables called "CPU 8/4 Pin" & "CPU 8 Pin".


    Can anyone help me? :'(
     
    Last edited: Mar 22, 2015
  2. pandlouk

    pandlouk Registered Member

    Joined:
    Jul 15, 2007
    Posts:
    2,560
    Check this link http://www.seasonicusa.com/NEW_X-series_1050-1250.htm
    JPWR1 -> cable Main Power (20/24P) (1 cable)
    JPWR2 -> cable EPS12V(8P) (1 cable)
    JPWR3 -> cable EPS12V/ATX12V(8P/4P) (1 cable) (connect only 4P)
    JPWR4 -> cable PCI-E 6P/8P (8 cables) (connect only the 6P)

    Panagiotis
     
  3. paulescobar

    paulescobar Registered Member

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    Sep 22, 2008
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    Pandlouk,

    Thank you so much for your help!

    After comparing your response, and other sources, I've figured this out on a basic level.

    Essentially, the JPWR2 & JPWR3 ports on the Motherboard control CPU power.
    JPWR2 is required for normal usage, and can use either CPU cable.
    JPWR3 is only required in cases of serious over-clocking. This requires the use of both CPU cables (which are designed differently because of how the Power Supply ports are configured).
     
  4. pandlouk

    pandlouk Registered Member

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    You're welcome.

    Correct, but the second cpu cable is not necessary only for overclocking. It should also be needed if your CPU has 6 or 8 cores even if you won't overclock.
    Since it is your first assembly, pay attention to take advantage of cable management holes of the case. Organising the cables (hiding them at the side) allows better airflow and will make future maintenance easier.

    Enjoy your new toy.:)
    Panagiotis
     
  5. paulescobar

    paulescobar Registered Member

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    Sep 22, 2008
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    Wow! Before I got this message alert, I was actually going through this dilemma in my head...connect the second CPU cable or not?

    The CPU I have for this setup is a "i7-4790K". Not "6 or 8 cores", only 4.
    But still...woud it hurt to add the extra cable and feed more power?
    Plan is to learn over-clocking over the next months, so am thinking that I might as well just add the second cable now.
     
  6. pandlouk

    pandlouk Registered Member

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    I see no problem plugin it even if you don't overclock. The motherboard will simply drain the needed power and no more than that.

    Panagiotis
     
  7. paulescobar

    paulescobar Registered Member

    Joined:
    Sep 22, 2008
    Posts:
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    To all,

    I have a follow-up question about my Seasonic PSU "PCI-E cables".

    The way my PCI-E cables are designed is...
    There's one end which is a single cable with a 12 hole connector...that goes into the PCI-E port on my power supply.
    But then the other end splits out into two different cables, with each having a sort of 6/2 connector.

    So regarding the end that splits out into two different cables...
    Can each be used on different PCI-E devices?
    Or is it the case that because my PSU has 3 PCI-E ports (and 3 of the cables I described)...that only 3 PCI-E devices can be powered?
     
  8. CrusherW9

    CrusherW9 Registered Member

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    Location:
    United States
    The reason for the 6/2 connector is that graphics cards have two types of power connectors. A 6 pin, and an 8 pin. The 6/2 connector allows you to use the same cable for either types. The reason it splits into 2 of the 6/2 connectors is because high end graphics cards can have 2x6 pins, 2x8 pins, or 1x6 pin and 1x8 pin. So you'd use both connectors in 1 graphics card. If you have two graphics cards, each with 1 6 pin, you could use both 6 pins on the 1 cable to connect both of them. The power supplied across these types of connectors is a standard. PCI lane is 75w, 6 pin is 75w, 8 pin is 150w. So what's the difference if you have 1 gpu with 2 6 pins drawing 150w or 2 gpu's with 1 6 pin each still drawing 150w?
     
  9. paulescobar

    paulescobar Registered Member

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    Sep 22, 2008
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    Thanks for the explanation!
    The highlighted part answers it well!
     
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