The Edge slot option is visible after connecting an additional +12 V power supply and a card to the GPGPU riser. Without an installed card, the slot is not detected. And the system only sees 2 GPU cards 16x. The third - no, but she sees the 4x SSD card. On 3 16x cards, the system lacks signal lines.Question: I see on your monitor screen that your BIOS shows the option ["edge slot" <enabled>] under "PCI configuration". Was this "edge slot"- option visible already before you connected a GPU card, or did this option only become visible in the BIOS after you connected the GPU card to the edge slot?