# Mellum2-12B-A2.5B-Instruct vs Ornith-1.5-397B

> Side-by-side benchmark comparison for Mellum2-12B-A2.5B-Instruct and Ornith-1.5-397B across agentic, coding, multimodal, knowledge, reasoning, multilingual, and math tasks.

- Canonical page: https://benchlm.ai/compare/mellum2-12b-a2-5b-instruct-vs-ornith-1-5-397b
- Last updated: October 2, 2026

- Shared sourced benchmarks: 2
- HTML indexing: indexable
- Ranking lane: BenchAlign v5.8

## Quick Verdict

Evidence is too thin for a benchmark verdict: Mellum2-12B-A2.5B-Instruct and Ornith-1.5-397B share only 2 sourced benchmark rows.

## Summary

- Only 2 shared sourced benchmark rows are available. That is not enough for a broad capability verdict, so this mirror does not name an overall winner.
- Ornith-1.5-397B has the larger published context window at 262K.

## Model Snapshot

| Property | Mellum2-12B-A2.5B-Instruct | Ornith-1.5-397B |
|----------|----------|----------|
| Creator | JetBrains | Ornith AI |
| Type | Open Weight | Open Weight |
| Reasoning | Non-Reasoning | Reasoning |
| Context | 128K | 262K |
| Independent public score (not head-to-head) | null | 62.72 |
| Benchmarks Covered | 6 | 18 |
| Pricing (input/output) | N/A | $0.00 / $0.00 |

## Category Breakdown

### Agentic

- Winner: Insufficient shared evidence
- Mellum2-12B-A2.5B-Instruct public-lane score: Coming soon
- Ornith-1.5-397B public-lane score: 56.8 (Estimated · #29/119)

| Benchmark | Mellum2-12B-A2.5B-Instruct | Ornith-1.5-397B | Winner |
|-----------|-----------|-----------|--------|
| BFCL v4 | 44.2% | Coming soon | Coming soon |
| Terminal-Bench 2.1 | Coming soon | 86.1% | Coming soon |
| HLE w/ tools | Coming soon | 56.1% | Coming soon |
| MCP Atlas | Coming soon | 80% | Coming soon |
| Toolathlon-Verified | Coming soon | 71.2% | Coming soon |
| WideResearch | Coming soon | 80.8% | Coming soon |
| BrowseComp | Coming soon | 86.6% | Coming soon |
| Claw-Eval | Coming soon | 81.4% | Coming soon |

### Coding

- Winner: Insufficient shared evidence
- Mellum2-12B-A2.5B-Instruct public-lane score: Coming soon
- Ornith-1.5-397B public-lane score: 54.7 (Estimated · #34/144)

| Benchmark | Mellum2-12B-A2.5B-Instruct | Ornith-1.5-397B | Winner |
|-----------|-----------|-----------|--------|
| LiveCodeBench v6 | 37.2% | Coming soon | Coming soon |
| Terminal-Bench 2.1 | Coming soon | 86.1% | Coming soon |
| SWE-bench Verified | Coming soon | 86% | Coming soon |
| SWE-bench Pro | Coming soon | 65.1% | Coming soon |
| SWE Multilingual | Coming soon | 79.6% | Coming soon |
| DeepSWE | Coming soon | 56.0% | Coming soon |
| frontierBench | Coming soon | 13.5% | Coming soon |
| NL2Repo | Coming soon | 59.5% | Coming soon |

### Knowledge

- Winner: Insufficient shared evidence
- Mellum2-12B-A2.5B-Instruct public-lane score: Coming soon
- Ornith-1.5-397B public-lane score: 63.3 (Estimated · #36/171)

| Benchmark | Mellum2-12B-A2.5B-Instruct | Ornith-1.5-397B | Winner |
|-----------|-----------|-----------|--------|
| MMLU-Redux | 78.1% | Coming soon | Coming soon |
| GPQA | 40.9% | 92.8% | Ornith-1.5-397B |
| GPQA-D | 40.9% | 92.8% | Ornith-1.5-397B |
| HLE | Coming soon | 44.6% | Coming soon |
| HLE w/o tools | Coming soon | 44.6% | Coming soon |

### Instruction Following

- Winner: Insufficient shared evidence
- Mellum2-12B-A2.5B-Instruct public-lane score: Coming soon
- Ornith-1.5-397B public-lane score: Coming soon

| Benchmark | Mellum2-12B-A2.5B-Instruct | Ornith-1.5-397B | Winner |
|-----------|-----------|-----------|--------|
| IFEval | 75.8% | Coming soon | Coming soon |

## FAQ

### Is there enough evidence to pick between Mellum2-12B-A2.5B-Instruct and Ornith-1.5-397B?

Not yet. The models share only 2 sourced benchmark rows, so this mirror reports the available measurements and metadata without naming a broad winner.

### What can I compare safely on this page?

Published pricing, context windows, model type, and individual shared benchmark rows are directly comparable. Independent overall scores and non-overlapping benchmark coverage are labeled separately and should not be read as a controlled head-to-head result.

## Related Comparisons

- [Mellum2-12B-A2.5B-Instruct vs Mellum2-12B-A2.5B-Thinking](/compare/mellum2-12b-a2-5b-instruct-vs-mellum2-12b-a2-5b-thinking)
- [Ornith-1.5-397B vs Mellum2-12B-A2.5B-Thinking](/compare/mellum2-12b-a2-5b-thinking-vs-ornith-1-5-397b)
- [Mellum2-12B-A2.5B-Instruct vs Ornith-1.5-35B-A3B](/compare/mellum2-12b-a2-5b-instruct-vs-ornith-1-5-35b-a3b)
- [Ornith-1.5-397B vs Ornith-1.5-35B-A3B](/compare/ornith-1-5-35b-a3b-vs-ornith-1-5-397b)

## Explore More

- [Mellum2-12B-A2.5B-Instruct profile](/models/mellum2-12b-a2-5b-instruct)
- [Ornith-1.5-397B profile](/models/ornith-1-5-397b)
- [Compare Pricing](/llm-pricing)
- [Alternative Finder](/tools/alternative-finder)
- [LLM Selector](/tools/llm-selector)
- [Overall Rankings](/best/overall)