"Please install your psus 4pin "

Miner8472Miner8472 Posts: 56Member
I connected my first pci-e riser to a rig and when I switch on the computer I get a message saying "Please install your PSU's 4 pin cable to the motherboards 4 pin connectors" (for extra power to the PCIE lanes). Do I have to do this? It is a powered riser with a gpu in it connected to a PCI-e x1 and there is one other GPU connected in the PCIx16 slot for a total of 2 GPUs.

The motherboard manual says when more than 3 GPUs are connected (i.e. 4 or more), then you must use this.

Comments

  • EMWEEEMWEE Posts: 59Member
    Check the 4-pin close to your CPU.
  • Miner8472Miner8472 Posts: 56Member
    Sorry I didn't do a very good job of the title! I believe this question is basically answered by the comments here:

    https://forum.ethereum.org/discussion/5976/please-install-the-psus-4-pin-power-cables-to-the-4-pin-connections-on-your-motherboard

    I have powered risers so I have not connected the 2 4pin molex connectors either end of the PCI-E slots with my set up of 2 GPUs. If I get 4 GPUs at any point I will do that.

    The CPU and Motherboard connections (these are not molex) are fully connected.
  • EMWEEEMWEE Posts: 59Member
    I dont have this motherboard but i guess you dont have to power the PCI-e slots with molex if u use powered risers.
  • headshot155headshot155 Posts: 61Member
    great, I'm going to unplug mine and see what happens, I was worried about instability in the cards but I'll try tonight..
  • erstwealerstweal MidwestPosts: 90Member
    You're fine without that molex. It's meant for use if you do not have powered risers. Or conversely, it's meant to power your boards when you plug them directly into the motherboard. The message will typically come back every time you restart the machine, but there is usually an option to tell it not to notify you any more.
  • headshot155headshot155 Posts: 61Member
    edited September 14
    I tried disconnecting the motherboard plugs on my 6 gpu on risers rig and it came up with the message before the boot screen. Pressing the N button doesnt allow the boot sequence to go any further on my h110 pro btc. There was me hoping I could save a few more watts!
    Post edited by headshot155 on
  • erstwealerstweal MidwestPosts: 90Member
    @headshot155 Are you saying that your rig works if you plug in the molex, but does not if you don't? If you have powered risers, it should not make a difference.
  • headshot155headshot155 Posts: 61Member
    edited September 14
    Exactly @erstweal. I've got powered risers (good quality ones) and if I unplug the 2 motherboard molex it won't allow me to boot. Simply comes up with a picture saying I need to plug them in, I've pressed every key and I can't get past it. Is there a bios setting to surpress the message?
  • erstwealerstweal MidwestPosts: 90Member
    No, just the N worked for me. By any chance are you running windows? If so, try just 5 GPUs and see if that works.
  • Miner8472Miner8472 Posts: 56Member
    In my motherboard manual (ASRock H81 btc pro R2.0) it says that if you have more than 3 GPUs plugged in you must plug in the molex to the PCI lanes. ASRock may try and force this as the motherboard does not have any features to detect the power in the risers if that makes sense. This may be the case even though it may not be needed.

    Slightly off topic: A useful tip I found out yesterday was after chiding myself for not buying a PSU with more molex connectors (I want to use Molex direct from the PSU for future cards) I actually read that you can connect the Molex (perif) cables to the Sata ports on the EVGA Gold G2 PSUs. So as long as you have the perif cables you are good. (Double check this though as I haven't done that yet lol). It might also be the case with other brands.

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