z370 Taichi (8th gen) SLI not working

Zenome wrote: Hi, I just received my second 1080 ti. I connected them to PCI slots 2 and 4 with the ASRock supplied SLI connector. Slot 2 is working slot 4 is not. Both cards have the power LED lit so it is not a matter of PSU. I switched slot positions, and slot 2 was working, slot 4 was not, so it isn't a matter of the card. I tried w/out the SLI connector, same result. Finally, single card configuration works in both slot 2 and slot 4. Please help ASAP.  I have a short time before I can RMA as I am traveling and all the hardware needs to come with me.  I doubt it's a MB hardware issue, since both slots seem to work, just not together;but who knows. Thanks in advance!

You did not explain how the card in the PCIE4 slot, while connected is SLI, is not working, or how you know it is not working. Or what you mean by a slot not working while connected in SLI.

Do you have any other card/device in any of the PCIe slots besides the video cards?

In the UEFI/BIOS, in the Tools screen, using the System Browser feature, are both cards recognized in the PCIe slots?

In Windows, Device Manager, do both cards appear in Display adapters when both are in the PCIE2 and PCIE4 slots?

Both 1080ti cards are the same manufacture and model?

Have you enabled and configured SLI in the NVIDIA Control Panel software? Are both cards detected in NVIDIA Control Panel?

Which NVIDIA driver version did you install?

What version of Windows are you using?

What version of Windows are you using? Windows 10 by default will install/update the video card driver whenever it detects a new/different version is available. That has caused a lot of trouble for me personally. New driver installations will reset configurations like SLI, so worth checking.

Apparently you don't have another SLI bridge to use?

The power LED on a card illuminating does not mean it has adequate power. What is the full model name/number of your PSU?

Did you try clearing the UEFI/BIOS after installing both cards in the board?

While we have very little detail to go by, you seem hardly at the point where an RMA of the video cards or boards will do you any good.