One flag makes Qwen3-4B beat Llama-3.1-8B on a 16 GB Mac — at half the RAM

On an M3 MacBook Air, Qwen3-4B with the thinking trace turned off scores 20/21 on a verifiable suite — beating Llama-3.1-8B's 18/21 at half the memory and nearly double the speed. With thinking on, the same model drops to 7/21. The flag is enable_thinking=False, and here's exactly what it changes and why it matters.