The system cannot process requests with two GPUs.
The system cannot process requests with two GPUs.
The secondary GPU should operate smoothly even with four lanes. PCIe compatibility is indeed strong. I'm using a PCIe 3.0 x16 card in a PCIe 1.1 x8 slot on a secondary system, and it functions without problems, albeit slower. Intel's documentation indicates support for configurations like 1x16 plus 4 lanes or 2x8 plus 4 lanes. This suggests the chipset and CPU can handle two cards directly from the CPU or up to sixteen from the CPU with one from the chipset. The manufacturer's guidance implies the board layout allows a second card in such a configuration. It's not unusual for an x16 slot to have only four or eight lanes electrically, and some boards even include x1 and x4 slots for larger cards. Asus might have chosen a full x16 slot without pins instead of a more restrictive design. That's just background.
You're puzzled because the 5700 XT supports plenty of PCIe lanes, yet you're not seeing any output.
Sorry to hear that. It seems the 5700 XT isn't compatible with your setup, but I checked other options too—plugging in the 7900 XT didn't help either. I wonder if Asus might not support graphics cards from the lower 16x slot?
Update quickly: The system suddenly started using both GPUs this morning, but after roughly 30 seconds it froze and stopped working. After turning it off, I accessed the BIOS with both GPUs, yet it became unresponsive again within about half a minute. Since then, I haven’t managed to get the system to operate with both GPUs. I’ve also noticed that when posting fails, the green/yellow “boot” light stays on.