A measured audit of Llama-3.1-8B on a rented L4: what vLLM's real, untouched default actually costs, what FP8 quantization gets you on top of it, and why a plausible-looking concurrency guess cost throughput instead of adding it. Every number here is measured, including a second, larger benchmark pass that fixed a real gap the first one had.

Jul 14, 2026