Dual 4090 setup, black screen issue

Hello,

I am experiencing an issue with my machine that has two RTX 4090 GPUs. When I use only one 4090, everything works fine. However, when I install both GPUs, the screen goes black during boot process.

System specifications:

  • CPU: AMD Ryzen Threadripper 7960X (24 cores)
  • Motherboard: Gigabyte TRX50 AI TOP
  • PSU: ATX 1600 W ASUS ROG Thor

Could you also please advise how the following BIOS settings should be configured?

  • CSM (Compatibility Support Module)
  • Above 4G Decoding
  • Resize BAR
  • Secure boot
  • IOMMU

Thank you in advance!