Qwen 3.5 397B-A17B · Speculative Decoding

B300 FP8: MTP vs Off Speculative Decoding

Speculative decoding comparison of MTP versus Off on B300 FP8 (NVIDIA Blackwell) running Qwen 3.5 397B-A17B. Throughput, cost, and interactivity differences across LLM workloads. Use the chart controls below to switch sequences and metrics — same interactions as the main inference chart.

MTP acceptance-rate comparability

MTP acceptance-rate implementations differ across inference engines. Points from different engines are not directly comparable on the same curve — throughput and cost at matched interactivity may reflect engine-level differences rather than pure speculative decoding gains. Interpret cross-engine comparisons with caution.

MTP posts 2963 tok/s/GPU for $0.22 per million tokens at 67 tok/s/user on Qwen 3.5 397B-A17B (B300 FP8); Off posts 1169 tok/s/GPU for $0.56. MTP is 156% cheaper per token; MTP delivers 154% more tok/s/GPU. Draft-token acceptance rates determine whether speculative decoding helps or hurts at a given concurrency level.

Throughput at 94 tok/s/user on Qwen 3.5 397B-A17B (B300 FP8): MTP hits 1913 tok/s/GPU, Off hits 731. Per-million costs land at $0.34 and $0.89 respectively. MTP is 158% cheaper per token; MTP delivers 162% more tok/s/GPU. Speculative decoding trades extra compute on draft tokens for fewer decoding steps — the payoff depends on sequence length and batch size.

Toward the upper edge of the 40–147 tok/s/user interactivity band, at 120 tok/s/user on Qwen 3.5 397B-A17B (B300 FP8): MTP runs 1299 tok/s/GPU at $0.49/M tokens, Off runs 484 at $1.34/M. MTP is 171% cheaper per token; MTP delivers 168% more tok/s/GPU. Gains from speculative decoding vary by workload; short-output prompts tend to benefit less. (Numbers reflect this URL's pinned 1k/1k · fp8 workload — changing sequence or model updates both the table and chart; the table stays pinned to this page's precision, so precision toggles in the controls affect the chart only.)

Qwen 3.5 397B-A17B: B300 FP8 MTP versus Off speculative decoding comparison at matched interactivity levels
B300 FP8 MTP versus Off speculative decoding comparison for this page's canonical default workload.
Interpolated from real benchmark data. Edit target interactivity values below to compare at different operating points.
Metric
Interactivity (tok/s/user)
Interactivity (tok/s/user)
Interactivity (tok/s/user)
Throughput (tok/s/gpu)
MTP:2962.5Off:1168.5
MTP:1913.1Off:731.3
MTP:1299.5Off:484.3
Cost ($/M tok)
MTP:$0.217Off:$0.557
MTP:$0.344Off:$0.889
MTP:$0.493Off:$1.337
tok/s/MW
MTP:1365222Off:538500
MTP:881623Off:337022
MTP:598835Off:223202
Concurrency
MTP:~90Off:~36
MTP:~42Off:~16
MTP:~23Off:~8

Inference Performance

Inference performance metrics across different models, hardware configurations, and serving parameters.

Vendor:
Aggregation:
Spec Decoding: