Nemotron vs. OpenAssistant

Overview

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.

Initial release: 2025-12-15

Current generation: Nemotron 3 Ultra

Reference

https://build.nvidia.com/nvidia/nemotron-3-ultra-550b-a55b/modelcard

Further Reading

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

Overview

OpenAssistant is a project organized by LAION with aim of providing an open source alternative to ChatGPT. Its primary effort is to collected instruct examples to then tune existing LLMs. The first major release is available as part of Hugging Face's HuggingChat.

Initial release: 2023-04-15

Reference

https://open-assistant.io/

Further Reading

• https://www.youtube.com/watch?v=ddG2fM9i4Kk