AI TRENDS | SemiAnalysis Says Time-to-First-Token Latency Is Overemphasized in LLM Inference

SemiAnalysis said the commonly cited time-to-first-token (TTFT) metric in large model inference may be receiving disproportionate attention, arguing that inference systems are not simply about being as fast as possible. According to Odaily, SemiAnalysis said the core consideration is the trade-off between per-user interaction speed, measured as tokens per second per user, and overall throughput efficiency, measured as tokens per second per GPU. SemiAnalysis said TTFT has limited impact on user experience in most scenarios, while token generation speed during the output phase is the key variable. The firm added that only about 10% to 20% of inference tasks are truly constrained by latency, with most other scenarios relying more on optimizing throughput and cost efficiency.