Impact of PCIe 5.0 x8/x4 vs x8/x8 on Dual GPU Inference

A user asks whether running dual GPUs in a PCIe 5.0 x8/x4 configuration instead of x8/x8 causes significant performance hits for LLM inference.

• The inquiry concerns the Biostar Z890 Valkyrie motherboard, which supports three PCIe 5.0 slots connected to the CPU.
• Adding a SATA expansion card to the bottom slot drops the middle slot's bandwidth to x4 speeds.
• The user seeks to know if this reduction affects performance when models are fully loaded in VRAM versus using partial offloading.