I’m posting this as a warning for anyone building multi-GPU local LLM rigs with older workstation/HEDT boards. My setup (Node #04) Gigabyte X399 Designare EX Threadripper 1950X 128GB DDR4 4x RTX 3090 10GbE TP-Link/Aquantia NIC llama.cpp NCCL build vLLM for safetensors models I was getting weirdly disappointing multi-GPU results. The rig worked, all 4 GPUs were detected, VRAM was available, models loaded, but some workloads were underwhelming. Example: Mistral Medium 3.5 1...