Gigabyte 990FXA-UD3 Rev 4.0

golekiprogolekipro Member Posts: 6
Hi Everyone,
I have a rig running this motherboard, this board has 6 PCIe slots ( 2 16x, 2 4x, 2 1x), I can get 5 cards to work on this board under Linux. The 6th card does not work at all, in Linux logs, I see things like "Card Fell off the bus". I know it is funny :). But basically it means that the BIOS see's 6th Card, but OS can't use it when it tries to load drivers. As soon as I take that card off, system boots up fine and I can mine on 5 cards.

Has anyone else see this problem before with this version of the motherboard (rev 4.0)?

In BIOS I have enabled IOMMU and disabled unwanted stuff like 1394 ports and audio controller. I have also already tried Presence Detection jumping of port. It works for now with 5 cards and is stable, but I am wasted 25MH not able to squeeze more out of this card. Any help is appreciated. Thank you.


  • ecs87ecs87 Dekalb, ILMember Posts: 335 ✭✭✭
    I have the exact same board...ROYAL PAIN to get 6 cards working...until I swapped PSUs. New PSU led to no more BIOS hangs and Win10 instantly recognized all my 500 series cards (sry haven't used Linux for mining).
  • golekiprogolekipro Member Posts: 6
    That is interesting, my system is powered by 2 650 Watt PSU's. So I am pretty sure that power is not an issue. Having said that, one of my cards is an EVGA card that needs 2 8 pin power leads. You raise an interesting point, may be I need to balance the cards a bit across the 2 power supplies. I will try that tomorrow morning and report back.
  • curtisimocurtisimo Member Posts: 10
    I'm having a hell of a time getting 5 RX 480 cards to work on this mobo with Windows 10. The rig works flawlessly with ethOS but I was hoping to get a little more efficiency with Windows. When I finally got the system to log in with all 5 cards attached, Claymore and genoli both didnt detect any gpus. I just put the ethOS drive back in for now.
  • ecs87ecs87 Dekalb, ILMember Posts: 335 ✭✭✭
    edited June 25
    Fwiw I used 17.5.2 for the driver. The earlier one (I think 17.4.3) was nothing but headaches. The drivers needed to be patched afterwards but 6 cards are definitely possible on this board, it's just very picky.
  • golekiprogolekipro Member Posts: 6
    Ok I have tried various combinations, but nothing seems to work. I have narrowed it down to PCIE 1x Port 1. If the Riser is plugged into that port, I always get a crash in Kernel and root cause is nvidia driver. I think I have to try a various Kernel and driver combinations to really get to bottom of this, but it seems to me that the port might be faulty.

    BTW guys I forgot to mention I am using GTX cards so can't use ethOS to test.
  • curtisimocurtisimo Member Posts: 10
    I tried again this morning. Used DDU to remove all drivers then installed 17.5.2, patched and then tested with one card. Windows logs in and mines perfectly with one card. Once I plug in a second card, Windows freezes during login (the swirling dots eventually freeze up after I enter my password). I tried different PCIe ports and card combinations. No luck
or to comment.