GLM 5.2 Fast is the snappy serving of GLM 5.2—same open assistant brain, tuned for lower latency when you are chatting interactively. Our tests find nearly the same helpfulness and instruction following as standard 5.2, with a small trade in depth on the hardest multi-step asks. Empathy and creative writing stay in the same utilitarian band. Choose Fast when response time matters in a live conversation; stay on standard 5.2 when you can wait for a more deliberate finish.