cse-846 power cable options?

Discussion in 'DIY Server and Workstation Builds' started by PaperBlankets, Sep 27, 2019.

  1. PaperBlankets

    PaperBlankets New Member

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    I recently moved my unraid server from an atx case and a few scattered jbod enclosures to a single cse-846.

    What I didn't realize when I was starting the build, was even though I had redundant 900w power supplies, the power backplane/cable harness does not have any pcie power connectors.

    I have tried searching for an alternate 'Power distributer' like this one: https://store.supermicro.com/server...ibutor/pdb-pt813m-2424-power-distributor.html

    Does anyone have any suggestions for powering a few gpus/compute cards in this case?

    Edit: I found this post and am following up on some options listed on it.
    https://forums.servethehome.com/index.php?threads/supermicro-chassis-or-power-supply-to-gpus.18139/
     
    #1
    Last edited: Sep 28, 2019
  2. Drooh

    Drooh New Member

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    I’ve got several of the same server cases, along with various other supermicro cases. I’ve utilized several methods for achieving this.

    Not knowing your use case, or comfortability working with voltage, so I will just tell you what I have done.

    In one of my racks, I have several server cases which are multi-purpose non-CPU utilizes. Some where power is feeding other devices, some just acting as external drive enclosures, some that have several spare atx psu’s I utilize to power things.

    I have a case that has just GPU’s, 1600 watt supermicro redundant power supply. I snipped off all the connectors to blunt ends. Did the electrical calculations, and wired up and soldered the connections I needed. Works just fine.

    In some cases I had adapters in hand already, and used the adapters to connect gpu’s and other devices. I believe I got those adapters on amazon at some point, or from mouser, one or the other.

    In some cases, where I was just powering up a couple of GPU’s, I have a case that houses 5 atx power supplies, I bought a mining psu adapter from amazon, which kicks on the slave power supplies, when the server kicks on. Some people don’t like these adapters. Don’t take my word for it, but I believe the thought process is you wouldn’t want to feed the motherboard with two different power supplies and deal with the two different minor oscillations in voltage output. Some motherboards won’t turn on in this circumstance, it should be avoided. But I’ve never had issues powering GPU’s in this manner. That’s me, not asserting it should be replicated.
     
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  3. PaperBlankets

    PaperBlankets New Member

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    Thanks for your feedback!

    I have some cables on the way, to start with I am going to attempt to:

    Run an eps 8pin splitter, run both CPUs off of one 8pin cable.
    Ran an eps 8pin to dual 8pin pcie (Supermicro CBL-0424L)

    I would like to run unraid with a dedicated gpu for plex, and a dedicated gpu for compute in containers and vms (Only one will use the compute card at a time).

    I'm hoping to do this with dual PWS-920P-SQ's, but I can go to something larger if need be.
    I suspect this setup will work for a single 1080/2080/ type of deal, but adding a second card will be pushing it too far.

    I think I am planning to just see how this goes, and then I will look into other options for more power.

    For the first pass I am mostly looking to:
    • Keep as much stock supermicro as I can
    • Keep everything in the single CSE-486

    When I add a 2nd card I bet I will have to start looking at powering the second card in some other way. I suspect I will need a HDPLEX psu or something else discreet if I don't want to expand out of the CSE-486.
     
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  4. 9jack9

    9jack9 New Member

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    @PaperBlankets Did you get your cables in, any success? I am attempting to do something similar as you, I want to use a Quadro 4000 RTX for Plex transcoding, and a compute/gaming GPU for use in VMs (likely most powerful GeForce card I can run with just 1 8-pin PCI-e connector). I would also like to use the PWS-920p-SQ power supply (I can purchase two).
     
    #4
  5. PaperBlankets

    PaperBlankets New Member

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    Hi @9jack9, I bought all the things.

    I am running two of these to get power from the 8 pin pcie connector
    Supermicro CBL-0424L GPU Regular 8-pin Converter Power Cable

    One 8 pin from the psu is powering both of the CPUs via this splitter: https://www.amazon.com/COMeap-Express-Adapter-Braided-Y-Splitter/dp/B072JR4H3N

    I ran two of these to get power from the molex connectors as well: Darkside 3-Way 4-Pin MOLEX Power Y-Cable Splitter - Jet Black (DS-0142) - Newegg.com
    Those molex connecters are attached to these: Coboc 2LP4PCIE8-6 6.1 in. Dual 4-pin Molex LP4 to 8 Pin PCI Express Video Card Power Adapter Converter Cable - Newegg.com

    I have not been able to get my motherboard to recognize the second GPU I tried. It seems to be an issue with my pcie slot.
    So at the moment I am just running a 1070 with encoding unlocked. I have a plex docker instance that uses the gpu, and one that does not so I can take the gpu back for a vm as needed. Eventually I will buy another gpu to try but it has just not been a priority yet.

    So all in all I have 4x 8 pin connectors to use for videocards. But as I said below, I don't have a 2nd or 3rd gpu at this time to use in the setup.
     
    #5
    Last edited: Dec 2, 2019
  6. 9jack9

    9jack9 New Member

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    Hi @PaperBlankets thanks for your reply.

    When you say the second 8-pin is split and powering the GPU, I assume you have a GPU that needs 2 8-pin connectors?

    Your second link is broken EDIT: looks fixed now, thanks! Also do you not have a X9DRi-F motherboard that can support 3 GPUs, or do you have 1 of your x16 PCIe slots used for something else?
     
    #6
    Last edited: Dec 1, 2019
  7. PaperBlankets

    PaperBlankets New Member

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    That's correct, I have 3 x16 (physical) slots.

    > When you say the second 8-pin is split and powering the GPU, I assume you have a GPU that needs 2 8-pin connectors?
    Correct

    The other cards I tried didn't show up though. They are all quite old, and were sitting in storage for a while (and I suspect are no longer functional Zotac 980ti arctic storm, and a Gigabyte 780 windforce).

    I'll try to remember to post here if/when I buy a new GPU and give it a shot

    Edit: I cleaned up my wording in the post above, the details on the 8pin pcie splitter were not very clearn.
     
    #7
  8. 9jack9

    9jack9 New Member

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    #8
  9. PaperBlankets

    PaperBlankets New Member

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    Hey @9jack9,

    I grabbed a 2080 super the other day and it's working as expected.

    1070 ti 8pin
    2080 super 8pin + 6pin

    I'm powering the 8pin on the 1070 and the 6 pin from the 2080 via the pci express power connection.

    I'm powering the 8 pin on the 2080 from the 4 pin molex to pcie power.

    I have not hit load on both cards, but it seems solid (the 1070 is just Plex, and I don't think it represents a significant power load).

    It's a shame the ram slots interfere with the last pcie slot:
    Imgur
    The thermal performance would be much better if I could have ran the 2080 in the lowest slot, allowing both cards to receive fresh air
     
    #9
    Last edited: Dec 8, 2019
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