Speculative decoding
RSD
Reward-Guided Speculative Decoding for Efficient LLM Reasoning
Superseded — cited as a baseline and beaten by newer methods
3 papers critique it · 2 beat it on benchmarks
What papers say
Verbatim critique sentences, each from a paper that cites RSD as a baseline.
Existing approximation algorithms such as K-SEQ sun2023spectr, MSS miao2024specinfer, RSD jeon2024recursive, and LP and vocabulary truncation khisti2025multi cannot guarantee near-optimal speedups: K-SEQ has a $(1-1/e)$-approximation guarantee, but the others have no formal guarantees.
“However, reward models are neural networks that require additional forward passes, substantially increasing the computational cost of SD.”
“Although effective in improving reliability, it incurs substantial drawbacks. First, reliance on external verifiers significantly increases latency and compute overhead. Second, pre-trained reward models are often specialized to specific tasks, making them difficult to generalize across diverse reasoning tasks.”
Beaten on benchmarks
Head-to-head results where a newer method reports beating RSD. Values are copied from the source paper's tables — verify against the cited paper.
InferSpec beats RSD
17.2 vs 15.7
Olympiad Bench · [General Model, Draft: Llama-3.2-Instruct and Target: Llama-3.1-Instruct]
From Tokens to Steps: Verification-Aware Speculative Decoding for Efficient Multi-Step ReasoningEASD beats RSD
52.12 vs 50.81
Average Accuracy · [72B target model + 7B draft model]
Entropy-Aware Speculative Decoding Toward Improved LLM Reasoning
What to use instead
Recent methods in the same sub-problem, not yet superseded in the knowledge base — arXiv benchmark leaders, not vetted production recommendations.
- FVO-SpecFuture Validity is the Missing Statistic: From Impossibility to $Φ$-Estimation for Grammar-Faithful Speculative DecodingMay 8, 2026
- From Tokens to StepsFrom Tokens to Steps: Verification-Aware Speculative Decoding for Efficient Multi-Step ReasoningApr 16, 2026
- Entropy-Aware Speculative Decoding (EASD)Entropy-Aware Speculative Decoding Toward Improved LLM ReasoningDec 29, 2025
- Global ResolutionGlobal Resolution: Optimal Multi-Draft Speculative Sampling via Convex MinimizationNov 19, 2025