Problem with gigabyte mobo

[Ceyflix-Rez]

I have a gigabyte motherboard B85-HD3 that's giving me a headache presently, I'm trying to run a 3080 GPU and a 1660 super on this motherboard but it's not working, whenever I removed the 3080 the mobo will boot up fine and vice versa, what can I do?

[miner29]

Have you tried using risers?  At least for the second card.

[MCcryptonia]

That motherboard is SLI compatible, if you are using the double pcie x16 slots the rtx3080 won't work, it's better to connect a card to a x16 slot and the other into a x1 slot using riser I'm sure it will work

[FP91G]

I have a gigabyte motherboard B85-HD3 that's giving me a headache presently, I'm trying to run a 3080 GPU and a 1660 super on this motherboard but it's not working, whenever I removed the 3080 the mobo will boot up fine and vice versa, what can I do?

Please update BIOS to the most recent version first. Install the 3080 video card in the upper X16 port, and connect the other video card through the raiser.
If it doesn't work, https://forum.giga-byte.co.uk/index.php
Do you have a BIOS loaded when installing 2x graphic cards?

[Refrumatrix]

1. Update the BIOS first
2. Don't bother using SLI cos it won't work for mining, it will interfere with each other if two GPUs are inserted in the available pcie x16 slots, use riser for one instead
3. This motherboard has other slots available two to three x1 pci slot available so connect one GPU on the x1 slot and another in the pcie x16 slot