I have a Dell R720, and I want to use it for LLama/AI. I can place a double-width GPU without any issues. When I install the second Double Width GPU, I receive a Plug and Play Training Error on Slot 4. The GPU works fine if I move it to the other slot. Is there a specific riser required to make this work?

GPU: AMD S7150 x2
Power Supply: 1100W
CPU: Dual E5-2650L v1