Researchers baked 3x inference speedups directly into LLM weights — without speculative decoding

Researchers baked 3x inference speedups directly into LLM weights — without speculative decoding

AI’s New Speed Secret: How One Token Unlocks 3x Faster Responses

The AI industry is facing a mounting crisis: as reasoning models generate increasingly complex chains of thought, the computational costs are spiraling out of control. A groundbreaking collaboration between researchers at the University of Maryland, Lawrence Livermore National Labs, Columbia University, and TogetherAI has discovered a solution that delivers 3x throughput gains by embedding efficiency directly into model weights—no extra infrastructure required.

The Bottleneck Everyone’s Ignoring

Next-token prediction—the foundation of modern language models—forces AI to generate text one token at a time, creating a throughput ceiling that becomes painfully expensive when models produce thousands of reasoning tokens before delivering final answers. This bottleneck is especially brutal for reasoning models that frequently generate thousands of “chain of thought” tokens, leading to slow, expensive user experiences.

John Kirchenbauer, a doctoral candidate at the University of Maryland and co-author of the research paper, explains the shifting landscape: “As we move toward agentic workflows, the focus is shifting from overall throughput to single-user speed. Today, with ultra-long thinking traces being the norm and agentic outer loops multiplying out those costs even further, latency is becoming as equally important a dimension of overall serving efficiency as gross tokens per second per hardware unit.”

The Multi-Token Prediction Revolution

Multi-token prediction (MTP) offers a fundamentally different approach. Instead of predicting one token per forward pass, MTP trains models to produce multiple tokens simultaneously in a single computational step. This isn’t just incremental improvement—it’s a paradigm shift that could redefine how we deploy AI systems.

Other acceleration methods exist, but they come with significant drawbacks. Speculative decoding requires deploying and managing an auxiliary “drafting” model, which spends more absolute compute to draft and verify predictions. MTP, by contrast, “leverages a similar sort of tradeoff, it’s just simpler to serve and scientifically interesting in its own right,” Kirchenbauer notes.

The Training Breakthrough: Self-Distillation

The key innovation lies in how the models are trained. Traditional MTP approaches suffer from two critical problems: grammatical mismatch and degenerate repetition. When predicting multiple tokens independently, models might generate nonsensical phrases like “panda meat” instead of “panda bamboo,” or fall back to repeating common words like “the the the the…”

The researchers solved this through a novel self-distillation approach. A student model generates deterministic multi-token blocks, which a teacher model—a strong standard next-token prediction language model—evaluates for coherence and likelihood. If the student proposes a mismatched phrase like “lion bamboo,” the teacher assigns it a high loss, teaching the student to avoid that construction.

This approach is inspired by on-policy reinforcement learning. Unlike static supervised methods where training pairs are fixed in advance, the feedback here is dynamic, generated from the student’s own outputs in real time. The strong teacher also verifies the coherence of tokens, preventing the student model from learning degenerate outputs like repeated words.

The Magic Token: Simplicity Meets Power

The implementation is elegantly simple: “There are truly no modifications to the architecture except for the addition of a special token,” Kirchenbauer explains. By co-opting an unused slot in a model’s existing embedding matrix to act as an <MTP> mask token, the technique converts sequential operations into parallel ones.

“Any standard next token prediction language model can be adapted in this way… the internal implementation—MoE, windowed attention, SSM layers, etc.—are left untouched and present no barrier to adaptation.” For developers, this means the adaptation can be applied to models already in production without rebuilding pipelines.

Smart Decoding: ConfAdapt

Generating multiple tokens at once can still hurt accuracy at inference time. To maximize generation speed without sacrificing output quality, the authors introduce an adaptive decoding strategy called ConfAdapt.

ConfAdapt evaluates a confidence threshold—such as 90%—at each step. The model generates a block of tokens but only keeps those that meet or exceed this high-confidence threshold. When the upcoming text is highly predictable or structural, the model’s confidence is very high. It will accept and output a large chunk of tokens all at once, saving significant computational time on easy tokens. It then focuses its costly single-token passes on harder tokens that require more computational effort.

Real-World Performance That Speaks Volumes

The researchers tested their approach on popular open-weight instruction-tuned models, including Llama-3.1-8B-Magpie and the smaller, efficient Qwen3-4B-Instruct-2507. Both models were tuned on MetaMathQA, a dataset of synthetic grade school math problems that rely heavily on reasoning traces.

The results were compelling. Using ConfAdapt, the Llama-3.1-8B model achieved a 3x speedup with less than a 3% drop in accuracy on math benchmarks. The Qwen3-4B model achieved the same 3x speedup with a slightly higher 7% drop in accuracy. More aggressive settings could hit 5x speedups, though they came with steeper accuracy penalties.

How this translates to real-world tasks depends on predictability. “As the ConfAdapt approach naturally tailors the acceleration to the inherent entropy in the domain, when the model ‘knows’ exactly what comes next it can emit it in a single pass,” Kirchenbauer noted, leading to massive acceleration on predictable tasks while using more steps for uncertain outputs.

Enterprise Implications and Deployment Strategy

The speedups also transferred across domains not included in the multi-token prediction training phase, including tasks within the same domain as the training data, like math and reasoning, as well as open-ended tasks such as creative writing and summarization.

However, enterprises deploying these models for specialized tasks shouldn’t rely on transfer learning entirely. “Our recommendation would be to tune/adapt the model for MTP using samples from the special industrial domain,” Kirchenbauer advised. “The best performance is likely achieved if the MTP adaptation is performed using prompts from the deployment domain.”

The Road to Production

The research team has released their trained models on Hugging Face and will soon release the code for their MTP framework. Infrastructure teams integrating these models into vLLM or SGLang will need to account for changes in how batching and KV caching are handled—but that’s a one-time engineering investment, not an ongoing burden.

Kirchenbauer sees “no clear barriers to integration” and confirmed the team is “working with some systems experts to identify the shortest path to integration.” His advice for teams wanting to test the released models: start with toy prompts like counting or repeating a phrase to see ConfAdapt’s gains in action, then adapt the model using samples from your specific deployment domain for best results.

“Overall we do expect that a production-ready implementation of our approach could simplify the lifecycle of building and deploying low-latency agentic models,” Kirchenbauer concluded. “While existing acceleration techniques for NTP models focus almost solely on inference harnesses and logic, our approach just bakes some of the complexity into the model itself making it largely complementary to existing work.”


Tags: AI acceleration, multi-token prediction, model efficiency, self-distillation, ConfAdapt, agentic AI, reasoning models, latency optimization, throughput gains, Hugging Face models, vLLM integration, SGLang deployment, enterprise AI, model training, inference optimization

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