For dual GPUs, will there be any big impact to inference speeds when running in PCIe 5.0 x8/x4 vs x8/x8?

I bought the Biostar Z890 Valkyrie because it was on sale and had three PCIe 5.0 slots connected to the CPU (x16 or x8/x8 or x8/x4/x4), which I thought would be great for running dual GPUs for LLM inference. The problem is that now I want to add a SATA expansion card to the bottom PCIe slot, but this will drop the middle slot to x4 speeds. Would I see a performance hit for inference if I run the two GPUs in x8/x4 mode, both when the model if fully loaded into VRAM and when I have to use partial offloading?