OpenAI Ultrafast mode routing adds a limited-preview GPT-5.6 Sol tier that is up to 14x faster than Standard, forcing operators to split latency-critical traffic from cost-sensitive fallback lanes.
xAI Priority Processing adds service_tier=priority for Chat Completions and Responses, making latency a per-request routing and billing decision.
Zhipu AI's GLM-5.1-highspeed delivers 400 tokens per second via the TileRT inference engine — the same flagship capability as GLM-5.1 but with a throughput profile that reshapes routing decisions for real-time agent and coding workloads.
