I figured it out.
Moving it to the lowest x16 port on my motherboard fixed it (where I had a second GPU). That port is only x4 speeds, but that’s the exact amount needed for this card to reach close to maximum throughput on both 25Gb ports: 16Gb (PCIe 4.0 x1) x 4 lanes = 48Gb.
I had to remove the second GPU and replace those displays with a USB DisplayLink adapter. It’s not that big of a deal.
Separate issue: I’m having performance issues with SMB over fiber vs Ethernet.
Created a separate thread here: