Nemotron vs. OPT

Nemotron

Nemotron is NVIDIA's open model family for efficient reasoning, coding, long-context analysis, and agent orchestration. Nemotron 3 Ultra is the current flagship.

NVIDIA introduced the Nemotron 3 family in December 2025 with Nano, Super, and Ultra tiers. Nemotron 3 Ultra, released in June 2026, is a 550B-parameter hybrid Mamba-Transformer mixture-of-experts model with 55B active parameters and a one-million-token context window. It is optimized for long-running agent workflows, tool use, code, multilingual reasoning, and high-stakes retrieval. NVIDIA publishes the weights, training data, recipes, and fine-tuning workflows under the OpenMDW-1.1 license.

Further reading

• research.nvidia.com/labs/nemotron/Nemotron-3/
• developer.nvidia.com/blog/nvidia-nemotron-3-ultra-powers-faster-more-efficient-reasoning-for-long-running-agents/
• build.nvidia.com/nvidia/nemotron-3-ultra-550b-a55b/modelcard

OPT

Open Pre-trained Transformer Language Models (OPT) is part of the family of open source models designed to replicate GPT-3, with similar decoder-only architecture. It has since been superseded by models such as LLaMA, GPT-J, and Pythia.