# Llama 3.1 Nemotron Ultra 253B ![Organization](https://img.shields.io/badge/Org-NVIDIA-76b900) ![License](https://img.shields.io/badge/License-Llama%203.1-22c55e) ![Released](https://img.shields.io/badge/Released-Apr%202025-555) ![Params](https://img.shields.io/badge/Params-253B-blue) > **Quick answer:** Llama 3.1 Nemotron Ultra 253B is NVIDIA's April 2025 post-trained model built on Meta's Llama 3.1 405B base, scoring 74.1% BFCL v2 and 66.3% LiveCodeBench. It is NVIDIA's largest Nemotron model — above Nemotron Super 49B (73.7% BFCL v2) in function calling. ## At a Glance **Where Nemotron Ultra 253B leads** - 74.1% BFCL v2 — strong function calling, above Nemotron Super 49B (73.7%) - 66.3% LiveCodeBench — competitive coding performance at this size - Built on Llama 3.1 405B base — full Meta ecosystem compatibility - 128K context window (via Llama 3.1) **Where it lags** - 253B parameters: requires significant GPU memory (~500GB+ for inference) - Llama 3.1 license restrictions (not fully permissive for all commercial uses) - Less benchmark data than OpenAI/Google frontier models - April 2025 release — pre-dates some newer SOTA **Best for:** Enterprise deployments requiring large-scale reasoning with NVIDIA optimisation; tool-use and function-calling agent pipelines; teams using NVIDIA infrastructure. ## What Llama 3.1 Nemotron Ultra 253B Is Llama 3.1 Nemotron Ultra 253B is NVIDIA's April 2025 post-training of Meta's Llama 3.1 405B. NVIDIA's Nemotron series involves RLHF and preference optimisation on top of Meta's base models, producing variants that excel on tool-use, instruction-following, and agentic tasks. "Ultra" indicates the top tier in NVIDIA's Nemotron lineup for this generation, with "Super" (49B) being the mid-tier variant. At 253B parameters on Llama 3.1 base, it inherits the 128K context window while benefiting from NVIDIA's alignment training. ## Specifications | Field | Value | |---|---| | Organization | NVIDIA | | License | Llama 3.1 License | | HuggingFace | nvidia/Llama-3.1-Nemotron-Ultra-253B-v1 | | Release date | April 14, 2025 | | Base model | Llama 3.1 405B | | Parameters | 253B | | Modality | Text only | | Context window | 128K tokens | ## Pricing Open weights (Llama 3.1 License) — self-host via NVIDIA NIM or HuggingFace. Available via NVIDIA API Catalog. ## Public Benchmark Scores | Benchmark | Score | Source | Date | |---|---|---|---| | [BFCL v2](/benchmarks/bfcl-v3) | 74.1% | Benchgen evaluation | 2025-04 | | [LiveCodeBench](/benchmarks/livecodebench) | 66.3% | Benchgen evaluation | 2025-04 | ## Nemotron Ultra 253B vs Alternatives | Model | BFCL v2 | LiveCodeBench | Params | License | |---|---|---|---|---| | **Nemotron Ultra 253B** | 74.1% | 66.3% | 253B | Llama 3.1 | | [Nemotron Super 49B](/models/nvidia/llama-3-3-nemotron-super-49b-v1) | 73.7% | — | 49B | Llama 3.3 | | [Llama 3.1 405B Instruct](/models/meta/llama-3-1-405b-instruct) | — | — | 405B | Llama 3.1 | | [QwQ-32B](/models/qwen/qwq-32b) | 66.4% | — | 32B | Apache 2.0 | Nemotron Ultra 253B vs Super 49B: marginal BFCL gain (74.1% vs 73.7%) at ~5x the parameter cost. Super 49B is more efficient for most deployments. ## Related Models & Benchmarks - Compare: [Nemotron Super 49B](/models/nvidia/llama-3-3-nemotron-super-49b-v1) · [Llama 3.1 405B Instruct](/models/meta/llama-3-1-405b-instruct) · [QwQ-32B](/models/qwen/qwq-32b) - Benchmarks: [BFCL v3](/benchmarks/bfcl-v3) · [LiveCodeBench](/benchmarks/livecodebench) ## Frequently Asked Questions

What is Llama 3.1 Nemotron Ultra 253B?

NVIDIA's April 2025 post-training of Llama 3.1 405B, scoring 74.1% BFCL v2 and 66.3% LiveCodeBench. NVIDIA's largest Nemotron model optimised for function-calling and agentic tasks.

Is Nemotron Ultra 253B better than Nemotron Super 49B?

Marginally on BFCL (74.1% vs 73.7%) at ~5x parameter cost. For most deployments, Nemotron Super 49B offers better efficiency. Choose Ultra 253B only if you need maximum BFCL-class function calling and have the hardware.

--- *Specs from NVIDIA's Llama 3.1 Nemotron Ultra 253B release (April 2025) and Benchgen evaluations. Last updated 2026-07-24.*

Llama 3.1 Nemotron Ultra 253B v1 — Files