# Mellum2.1-12B-A2.5B-Thinking vs Nemotron 3 Ultra

> Side-by-side benchmark comparison for Mellum2.1-12B-A2.5B-Thinking and Nemotron 3 Ultra across agentic, coding, multimodal, knowledge, reasoning, multilingual, and math tasks.

- Canonical page: https://benchlm.ai/compare/mellum2-1-12b-a2-5b-thinking-vs-nemotron-3-ultra
- Last updated: October 8, 2026

- Shared sourced benchmarks: 4
- HTML indexing: indexable
- Ranking lane: BenchAlign v5.8

## Quick Verdict

Nemotron 3 Ultra leads by point estimate. Conditional score ranges do not establish rank confidence. Choose using the category evidence and your own workload tests.

## Summary

- Nemotron 3 Ultra has the higher overall point estimate 46.75 to 37. Conditional score ranges do not establish rank confidence.
- The biggest single benchmark swing is Terminal-Bench 2.1 in Agentic, with scores of 17.4% and 56.4%.
- Nemotron 3 Ultra also has the larger context window at 1M.

## Model Snapshot

| Property | Mellum2.1-12B-A2.5B-Thinking | Nemotron 3 Ultra |
|----------|----------|----------|
| Creator | JetBrains | NVIDIA |
| Type | Open Weight | Open Weight |
| Reasoning | Reasoning | Reasoning |
| Context | 128K | 1M |
| Overall Score | null | 46.75 |
| Benchmarks Covered | 7 | 24 |
| Pricing (input/output) | $0.00 / $0.00 | $0.00 / $0.00 |

## Category Breakdown

### Agentic

- Winner: Not comparable
- Mellum2.1-12B-A2.5B-Thinking public-lane score: Coming soon
- Nemotron 3 Ultra public-lane score: 27.2 (Supported · #93/122)

| Benchmark | Mellum2.1-12B-A2.5B-Thinking | Nemotron 3 Ultra | Winner |
|-----------|-----------|-----------|--------|
| Terminal-Bench 2.1 | 17.4% | 56.4% | Nemotron 3 Ultra |
| PinchBench | Coming soon | 90.0% | Coming soon |
| BrowseComp | Coming soon | 44.4% | Coming soon |
| τ³-bench results | Coming soon | 70.9% | Coming soon |
| HLE w/ tools | Coming soon | 37.4% | Coming soon |
| Terminal-Bench 2.1 (Vals) | Coming soon | 50.9% | Coming soon |

### Coding

- Winner: Not comparable
- Mellum2.1-12B-A2.5B-Thinking public-lane score: Coming soon
- Nemotron 3 Ultra public-lane score: 22.9 (Supported · #111/146)

| Benchmark | Mellum2.1-12B-A2.5B-Thinking | Nemotron 3 Ultra | Winner |
|-----------|-----------|-----------|--------|
| LiveCodeBench v6 | 82.0% | 89.0% | Nemotron 3 Ultra |
| SWE-bench Verified | 47% | 71.9% | Nemotron 3 Ultra |
| SWE-bench Pro | 28% | Coming soon | Coming soon |
| SWE Multilingual | Coming soon | 67.7% | Coming soon |
| SciCode | Coming soon | 44.6% | Coming soon |
| Terminal-Bench 2.1 | Coming soon | 56.4% | Coming soon |
| LiveCodeBench (Vals) | Coming soon | 86.0% | Coming soon |
| SWE-bench (Vals) | Coming soon | 69.0% | Coming soon |

### Reasoning

- Winner: Not comparable
- Mellum2.1-12B-A2.5B-Thinking public-lane score: Coming soon
- Nemotron 3 Ultra public-lane score: 51.8 (#27/28)

| Benchmark | Mellum2.1-12B-A2.5B-Thinking | Nemotron 3 Ultra | Winner |
|-----------|-----------|-----------|--------|
| CritPt | Coming soon | 3.1% | Coming soon |
| LongBench v2 | Coming soon | 61.9% | Coming soon |

### Knowledge

- Winner: Not comparable
- Mellum2.1-12B-A2.5B-Thinking public-lane score: Coming soon
- Nemotron 3 Ultra public-lane score: 49 (Estimated · #72/174)

| Benchmark | Mellum2.1-12B-A2.5B-Thinking | Nemotron 3 Ultra | Winner |
|-----------|-----------|-----------|--------|
| MMLU-Redux | 87.8% | Coming soon | Coming soon |
| GPQA-D | 64.6% | 87.0% | Nemotron 3 Ultra |
| GPQA | Coming soon | 87% | Coming soon |
| HLE | Coming soon | 26.7% | Coming soon |
| HLE w/o tools | Coming soon | 26.7% | Coming soon |
| MMLU-Pro | Coming soon | 86.8% | Coming soon |
| GPQA Diamond (Vals) | Coming soon | 86.1% | Coming soon |
| MMLU-Pro (Vals) | Coming soon | 85.8% | Coming soon |

### Multilingual

- Winner: Not comparable
- Mellum2.1-12B-A2.5B-Thinking public-lane score: Coming soon
- Nemotron 3 Ultra public-lane score: 89.2 (#7/16)

| Benchmark | Mellum2.1-12B-A2.5B-Thinking | Nemotron 3 Ultra | Winner |
|-----------|-----------|-----------|--------|
| MMLU-ProX | Coming soon | 83% | Coming soon |

### Instruction Following

- Winner: Not comparable
- Mellum2.1-12B-A2.5B-Thinking public-lane score: Coming soon
- Nemotron 3 Ultra public-lane score: 87.4 (#28/125)

| Benchmark | Mellum2.1-12B-A2.5B-Thinking | Nemotron 3 Ultra | Winner |
|-----------|-----------|-----------|--------|
| IFEval | 90.6% | Coming soon | Coming soon |
| IFBench | Coming soon | 81.7% | Coming soon |

## FAQ

### Which is better overall, Mellum2.1-12B-A2.5B-Thinking or Nemotron 3 Ultra?

Nemotron 3 Ultra has the higher overall point estimate. Conditional score ranges do not establish rank confidence.

### How many benchmarks does Mellum2.1-12B-A2.5B-Thinking cover on BenchLM?

Mellum2.1-12B-A2.5B-Thinking currently has 7 sourced benchmark scores on BenchLM.

### How many benchmarks does Nemotron 3 Ultra cover on BenchLM?

Nemotron 3 Ultra currently has 24 sourced benchmark scores on BenchLM.

## Related Comparisons

- [Mellum2.1-12B-A2.5B-Thinking vs Claude Opus 5.5](/compare/claude-opus-5-5-vs-mellum2-1-12b-a2-5b-thinking)
- [Nemotron 3 Ultra vs Claude Opus 5.5](/compare/claude-opus-5-5-vs-nemotron-3-ultra)
- [Mellum2.1-12B-A2.5B-Thinking vs GPT-6 Astra](/compare/gpt-6-astra-vs-mellum2-1-12b-a2-5b-thinking)
- [Nemotron 3 Ultra vs GPT-6 Astra](/compare/gpt-6-astra-vs-nemotron-3-ultra)

## Explore More

- [Mellum2.1-12B-A2.5B-Thinking profile](/models/mellum2-1-12b-a2-5b-thinking)
- [Nemotron 3 Ultra profile](/models/nemotron-3-ultra)
- [Compare Pricing](/llm-pricing)
- [Alternative Finder](/tools/alternative-finder)
- [LLM Selector](/tools/llm-selector)
- [Overall Rankings](/best/overall)