Llama Nemotron Ultra 253BOpen Weight
Released
Llama Nemotron Ultra 253B is an AI model released by NVIDIA on Tuesday, Apr 8 2025, 21 days after Llama Nemotron (Nano/Super). It is an open-weight model — the trained weights are available to download and run. It is a 253B parameter model. Benchmark results (shown below) cover LiveCodeBench, and GPQA Diamond.
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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.
Frequently asked questions
Llama Nemotron Ultra 253B was released by NVIDIA on Tuesday, Apr 8 2025.