Nemotron 3 Ultra is built for developers who run AI agents that need to plan, call tools and reason over many turns. As those agents work longer, token counts explode and inference cost rises quickly. The model solves this by using a Mixture‑of‑Experts architecture with 550 billion total parameters but only 55 billion active for each token. This sparse design gives high accuracy per active parameter while keeping compute low.
Instead of a pure Transformer, Nemotron 3 Ultra mixes Mamba layers with a few Attention layers. Mamba handles very long sequences with sub‑quadratic scaling, so the cost of generating each new token stays flat even when the context grows to one million tokens. The limited Attention layers preserve precise recall where it matters most.
Three engineering tricks boost the model further. LatentMoE trades hidden‑dimension width for more routed experts, improving accuracy per parameter. Multi‑Token Prediction lets the model guess several future tokens in one pass, enabling native speculative decoding and faster generation. NVFP4 pre‑training shows that stable 4‑bit quantization works at this scale, cutting memory footprint without losing quality.
Post‑training combines Supervised Fine‑Tuning, Reinforcement Learning with Verifiable Reward and Multi‑teacher On‑Policy Distillation. MOPD pulls dense, token‑level guidance from many specialist teachers, giving the student a richer signal than sparse environment rewards alone. The process runs asynchronously and can be iterated for steady gains.
For agents that need to trade speed for a small accuracy drop, the model offers three reasoning modes. Medium‑effort uses about 2.5× fewer tokens than regular mode with roughly a 7 % accuracy loss, lowering cost per turn in high‑volume workflows.
In practice, Nemotron 3 Ultra delivers up to six times higher throughput than comparable open LLMs on decode‑heavy tasks while maintaining on‑par accuracy. It supports a one‑million‑token context, scores strongly on agentic benchmarks and shows the lowest hallucination tendency in its class. The released NVFP4 checkpoint runs natively on Blackwell GPUs and as W4A16 on Hopper and Ampere, fitting comfortably on a single 8‑GPU node.
Use Nemotron 3 Ultra when you need long‑running, tool‑using agents that stay accurate, cheap and fast even as conversations stretch to hundreds of thousands of tokens.
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