I can't see the image very clearly but it looks like you are not plugging anything into the 16X PCI-E slot.
Plug the the first card into the 16x slot using a 1x riser (It fits) just doesn't use all the space on the slot.
A PC generally looks for a graphics card on the 16x slot at boot to output to the monitor. You can disable onboard graphics/audio/com ports and all unnecessary devices in BIOS.
The cards must be powered as well as the Risers. The card will draw power from the Riser and the 6/8 pin power cables connected to it.
I could be wrong but the power to the MB near the PCI-e slots is not necessary when using powered risers. I think they are there if you use risers that are not powered.
I know on the Biostar TB-250 you dont have to plug in the molex power cables if you have powered risers.
Plug the the first card into the 16x slot using a 1x riser (It fits) just doesn't use all the space on the slot.
A PC generally looks for a graphics card on the 16x slot at boot to output to the monitor. You can disable onboard graphics/audio/com ports and all unnecessary devices in BIOS.
The cards must be powered as well as the Risers. The card will draw power from the Riser and the 6/8 pin power cables connected to it.
I could be wrong but the power to the MB near the PCI-e slots is not necessary when using powered risers. I think they are there if you use risers that are not powered.
I know on the Biostar TB-250 you dont have to plug in the molex power cables if you have powered risers.
Yeah, the main PCIe slot is right now empty: https://ibb.co/kOV045 That's because right now I don't have any 1X risers, secondly I didn't saw any rigs that had GPUs in that slot...
This MB has integrated GPU on it: https://www.gigabyte.com/MicroSite/462/mining.html, so without risers this is what is working.
I removed the two 12V connectors on the MB near the PCIe 16X slots. Can anyone confirm that these two power connectors doesn't need to be plugged in?