Single-stream decode with one variable between the two columns of this comparison.
Both columns were measured on 2026-08-01 in one window, one container, one engine install, on the same 4x B200 cards, run back to back with an idle VRAM drain between them, and the comparison tool verified the request profiles identical across the arms before rendering any number.
The baseline column is this same configuration with speculative decoding off, not a different engine and not a failed serve.
The optimized column enables the DSpark speculative decoding that ships fused inside the DeepSeek-V4-Flash-0731 checkpoint, which the released engine does not enable on its own.
The throughput figures are per-request decode rates at concurrency 1, the speed one user experiences, not per-GPU figures and not node aggregates: 113.37 output tokens per second p50 with speculation off and 362.86 with it on.
The latency stats beside each column are end-to-end request times from the same runs: the optimized median request finishes in 3.1 seconds instead of 9.2, and its time to first token is 232.93 ms against 220.21, a cost of about 13 ms.
The profile, stated exactly: single-stream sequential, concurrency 1, 8 timed requests per arm, 1024 prompt tokens target, 1024 output tokens requested per request, temperature 0.0, ignore_eos on, streaming, a fixed seed, and 8 of 8 requests ok on each arm.
Know the boundary of this result before you deploy on it: the advantage is a low-concurrency fact, and the same window measured how it narrows with load on 32768-token-prompt workloads, plus 168 percent per GPU at concurrency 1, plus 33.6 percent at concurrency 8, and minus 6.9 percent at concurrency 32 where the median end-to-end time stays flat.
The optimized configuration also ran in the measurement slot that this campaign's A/A control series showed to be systematically disadvantaged, so the comparison understates the effect rather than overstating it.