Language model
Llama 3.1 Nemotron Ultra 253B
NVIDIA
- Released
- April 7, 2025
- Data date
- September 26, 2026
Llama 3.1 Nemotron Ultra 253B CPT v1 is an NVIDIA base model derived from Llama 3.1 405B Instruct and then continually pretrained. The model card names English and coding languages as its main intended uses. The reasoning checkpoint built on top of it, Llama 3.1 Nemotron Ultra 253B v1, remains a separate model identity and is linked there as a preview API.
The CPT v1 checkpoint has 253 billion parameters, supports up to 131,072 context tokens, and produces text. The open weights use NVIDIA's Open Model License. This base model is intended for further adaptation, not as a finished reasoning chatbot.
Popularity
12.5 / 100
Sources and data date
| Type | Evidence and data date |
|---|---|
| Additional source | models.dev catalog (retrieved September 26, 2026) |
| Additional source | NVIDIA Llama 3.1 Nemotron Ultra 253B CPT model card (retrieved October 2, 2026) · NVIDIA Llama 3.1 Nemotron Ultra 253B CPT v1 model card · Editorial description reviewed October 2, 2026 |
| Additional source | NVIDIA Nemotron reasoning model overview · Editorial description reviewed October 2, 2026 |
| Additional source | OpenRouter: Popularity index (derived), CC BY 4.0 |
| Additional source | Vercel AI Gateway: Popularity index (derived), CC BY 4.0 |
| Additional source | Creative Commons Attribution 4.0 |