Investigation of the slow (8-12s) qwen3-tts TTFB found the upstream
wrapper has 5 backend options. The advertised path to fast TTFB is
TTS_BACKEND=optimized (torch.compile + CUDA graphs + real-time
streaming). It loads cleanly but crashes the container during its
hardcoded warmup phase — silent exit (ExitCode 0, no traceback,
no OOM kill), repeats every ~22s under restart policy.
TTS_WARMUP_ON_START=false suppresses the factory-level warmup but
the optimized backend has its own internal warmup that fires
regardless and triggers the crash.
Updated the .env.example block to enumerate all 5 backend options
with their actual current behavior so future-Claude doesn't re-walk
this path. official is staying as the default.
vh
db42a7cc17