# Mellum2.1-12B-A2.5B-Thinking vs Ternary Bonsai 2 27B

> Side-by-side benchmark comparison for Mellum2.1-12B-A2.5B-Thinking and Ternary Bonsai 2 27B across agentic, coding, multimodal, knowledge, reasoning, multilingual, and math tasks.

- Canonical page: https://benchlm.ai/compare/mellum2-1-12b-a2-5b-thinking-vs-ternary-bonsai-2-27b
- Last updated: October 8, 2026

- Shared sourced benchmarks: 6
- HTML indexing: indexable
- Ranking lane: BenchAlign v5.8

## Quick Verdict

Ternary Bonsai 2 27B leads by point estimate. Conditional score ranges do not establish rank confidence. Choose using the category evidence and your own workload tests.

## Summary

- Ternary Bonsai 2 27B has the higher overall point estimate 53.43 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 52.8%.
- Ternary Bonsai 2 27B also has the larger context window at 262K.

## Model Snapshot

| Property | Mellum2.1-12B-A2.5B-Thinking | Ternary Bonsai 2 27B |
|----------|----------|----------|
| Creator | JetBrains | Prism ML |
| Type | Open Weight | Open Weight |
| Reasoning | Reasoning | Reasoning |
| Context | 128K | 262K |
| Overall Score | null | 53.43 |
| Benchmarks Covered | 7 | 21 |
| 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
- Ternary Bonsai 2 27B public-lane score: Coming soon

| Benchmark | Mellum2.1-12B-A2.5B-Thinking | Ternary Bonsai 2 27B | Winner |
|-----------|-----------|-----------|--------|
| Terminal-Bench 2.1 | 17.4% | 52.8% | Ternary Bonsai 2 27B |
| τ²-bench results | Coming soon | 80.2% | Coming soon |
| BFCL v3 | Coming soon | 74.9% | Coming soon |

### Coding

- Winner: Not comparable
- Mellum2.1-12B-A2.5B-Thinking public-lane score: Coming soon
- Ternary Bonsai 2 27B public-lane score: Coming soon

| Benchmark | Mellum2.1-12B-A2.5B-Thinking | Ternary Bonsai 2 27B | Winner |
|-----------|-----------|-----------|--------|
| LiveCodeBench v6 | 82.0% | 90.1% | Ternary Bonsai 2 27B |
| SWE-bench Verified | 47% | 60.8% | Ternary Bonsai 2 27B |
| SWE-bench Pro | 28% | Coming soon | Coming soon |
| BigCodeBench | Coming soon | 58.1% | Coming soon |
| Terminal-Bench 2.1 | Coming soon | 52.8% | Coming soon |

### Reasoning

- Winner: Not comparable
- Mellum2.1-12B-A2.5B-Thinking public-lane score: Coming soon
- Ternary Bonsai 2 27B public-lane score: 75.2 (Unranked · 1 rankable row)

### Multimodal & Grounded

- Winner: Not comparable
- Mellum2.1-12B-A2.5B-Thinking public-lane score: Coming soon
- Ternary Bonsai 2 27B public-lane score: Coming soon

| Benchmark | Mellum2.1-12B-A2.5B-Thinking | Ternary Bonsai 2 27B | Winner |
|-----------|-----------|-----------|--------|
| CharXiv (overall) | Coming soon | 80.0% | Coming soon |
| A-OKVQA | Coming soon | 86.8% | Coming soon |
| OmniDocBench 1.6 | Coming soon | 89.1% | Coming soon |
| RealWorldQA | Coming soon | 80.1% | Coming soon |
| OCRBench V2 | Coming soon | 56.9% | Coming soon |

### Knowledge

- Winner: Not comparable
- Mellum2.1-12B-A2.5B-Thinking public-lane score: Coming soon
- Ternary Bonsai 2 27B public-lane score: Coming soon

| Benchmark | Mellum2.1-12B-A2.5B-Thinking | Ternary Bonsai 2 27B | Winner |
|-----------|-----------|-----------|--------|
| MMLU-Redux | 87.8% | 89.1% | Ternary Bonsai 2 27B |
| GPQA-D | 64.6% | 85.8% | Ternary Bonsai 2 27B |
| GPQA | Coming soon | 85.8% | Coming soon |

### Instruction Following

- Winner: Not comparable
- Mellum2.1-12B-A2.5B-Thinking public-lane score: Coming soon
- Ternary Bonsai 2 27B public-lane score: 70.3 (#64/125)

| Benchmark | Mellum2.1-12B-A2.5B-Thinking | Ternary Bonsai 2 27B | Winner |
|-----------|-----------|-----------|--------|
| IFEval | 90.6% | 91.3% | Ternary Bonsai 2 27B |
| IFBench | Coming soon | 74% | Coming soon |

### Mathematics

- Winner: Not comparable
- Mellum2.1-12B-A2.5B-Thinking public-lane score: Coming soon
- Ternary Bonsai 2 27B public-lane score: 76.8 (Unranked · 4 rankable rows)

| Benchmark | Mellum2.1-12B-A2.5B-Thinking | Ternary Bonsai 2 27B | Winner |
|-----------|-----------|-----------|--------|
| GSM8K | Coming soon | 96.7% | Coming soon |
| MATH-500 | Coming soon | 98.8% | Coming soon |
| AIME 2025 | Coming soon | 95% | Coming soon |
| AIME26 | Coming soon | 95.8% | Coming soon |

## FAQ

### Which is better overall, Mellum2.1-12B-A2.5B-Thinking or Ternary Bonsai 2 27B?

Ternary Bonsai 2 27B 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 Ternary Bonsai 2 27B cover on BenchLM?

Ternary Bonsai 2 27B currently has 21 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)
- [Ternary Bonsai 2 27B vs Claude Opus 5.5](/compare/claude-opus-5-5-vs-ternary-bonsai-2-27b)
- [Mellum2.1-12B-A2.5B-Thinking vs GPT-6 Astra](/compare/gpt-6-astra-vs-mellum2-1-12b-a2-5b-thinking)
- [Ternary Bonsai 2 27B vs GPT-6 Astra](/compare/gpt-6-astra-vs-ternary-bonsai-2-27b)

## Explore More

- [Mellum2.1-12B-A2.5B-Thinking profile](/models/mellum2-1-12b-a2-5b-thinking)
- [Ternary Bonsai 2 27B profile](/models/ternary-bonsai-2-27b)
- [Compare Pricing](/llm-pricing)
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- [Overall Rankings](/best/overall)