SemiAnalysis: TTFT Overrated? LLM Inference Bottleneck Lies in Balancing Interactivity and Throughput

Odaily reports that SemiAnalysis has pointed out that the "time-to-first-token" (TTFT) often cited in large model inference may be receiving excessive market attention. The core dimension of an inference system is not that "faster is always better," but rather the trade-off between "single-user interaction speed (tok/s/user)" and "overall throughput efficiency (tok/s/GPU)." In most scenarios, TTFT has a limited impact on user experience; instead, the token generation speed during the decoding phase is the critical variable.

SemiAnalysis concludes that only approximately 10%–20% of inference tasks are truly latency-constrained, while the vast majority of other scenarios are more dependent on the optimization of throughput and cost efficiency.