# Llama Nemotron Ultra 253B

Llama Nemotron Ultra 253B is an AI model released by NVIDIA on Apr 8 2025. It has 253B parameters and open weight. At release it scored 76% on GPQA Diamond and 66.3% on LiveCodeBench.

## Facts

| Field | Value |
| --- | --- |
| Model | Llama Nemotron Ultra 253B |
| Developer | NVIDIA |
| Release date | Tuesday, Apr 8 2025 |
| Licensing | Open Weight |
| Parameters | 253B |

## Benchmark scores published at release

| Benchmark | Score | Source | What it measures |
| --- | --- | --- | --- |
| LiveCodeBench | 66.3% | Lab | Coding problems published so recently the AI can't have seen them in training — a contamination-free test of raw programming skill. Higher is better. |
| GPQA Diamond | 76% | Lab | Graduate-level science questions in biology, physics, and chemistry — hard enough that subject-matter PhDs score around 65%. Higher is better. |

## About Llama Nemotron Ultra 253B

Llama Nemotron Ultra 253B, released April 8, 2025, completed the reasoning family NVIDIA had announced at GTC three weeks earlier. It was compressed by neural architecture search from Meta's Llama 3.1 405B down to 253 billion parameters — sized deliberately so the strongest open reasoning model of the family fit a single 8-GPU H100 node — and post-trained for switchable step-by-step reasoning.

At launch NVIDIA reported 76.0% on GPQA Diamond and 66.3% on LiveCodeBench, competitive with DeepSeek-R1 — the model that had defined the open reasoning tier — at just over a third of R1's total parameter count. The weights and much of the post-training data went out openly, and Ultra stood as NVIDIA's open flagship until the in-house Nemotron 3 generation began that December.

## Questions and answers

### When was Llama Nemotron Ultra 253B released?

Llama Nemotron Ultra 253B was released by NVIDIA on Tuesday, Apr 8 2025.

### Who made Llama Nemotron Ultra 253B?

Llama Nemotron Ultra 253B was built by NVIDIA. The dominant AI chipmaker, publishing the open Nemotron model family. Ships weights, datasets and training recipes to seed demand for its hardware rather than to sell a chatbot.

### What benchmark scores did Llama Nemotron Ultra 253B get?

Llama Nemotron Ultra 253B reports 2 tracked benchmark scores — LiveCodeBench: 66.3%; GPQA Diamond: 76%. Scores are the figures published at release by NVIDIA.

### How many parameters does Llama Nemotron Ultra 253B have?

Llama Nemotron Ultra 253B is reported at 253B parameters.

### Is Llama Nemotron Ultra 253B open source?

Partly. Llama Nemotron Ultra 253B is an open-weight model: the trained weights are free to download and run locally or on your own infrastructure, but the training data and code are not fully released and the license may restrict some commercial uses. It is not open source in the strict sense.

### What came before and after Llama Nemotron Ultra 253B?

NVIDIA's previous tracked release was Llama Nemotron (Nano/Super) on Mar 18 2025, 21 days earlier. It was followed by Nemotron Nano 2 on Aug 18 2025.


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Canonical page: https://aireleasetracker.com/model/nvidia/llama-nemotron-ultra-253b
Full dataset: https://aireleasetracker.com/llms-full.txt · JSON: https://aireleasetracker.com/models.json
Source: AI Release Tracker (https://aireleasetracker.com). Benchmark scores are the figures published by the releasing lab at launch.