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

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

- Canonical page: https://benchlm.ai/compare/mellum2-12b-a2-5b-thinking-vs-ternary-bonsai-2-27b
- Last updated: September 18, 2026

- Shared sourced benchmarks: 5
- HTML indexing: indexable
- Ranking lane: BenchAlign v5

## Quick Verdict

Pick Mellum2-12B-A2.5B-Thinking if you want the stronger benchmark profile. Ternary Bonsai 2 27B only makes more sense when its price, context window, or workload-specific category wins matter more than the overall score.

## Summary

- Mellum2-12B-A2.5B-Thinking leads overall 52 to 50.78.
- The clearest category separation is in knowledge, where the averages are 46.8 for Mellum2-12B-A2.5B-Thinking and 50.6 for Ternary Bonsai 2 27B.
- The biggest single benchmark swing is GPQA in Knowledge, with scores of 57.6% and 85.8%.
- Ternary Bonsai 2 27B also has the larger context window at 262K.

## Model Snapshot

| Property | Mellum2-12B-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 | 50.78 |
| Benchmarks Covered | 6 | 21 |
| Pricing (input/output) | N/A | $0.00 / $0.00 |

## Category Breakdown

### Agentic

- Winner: Coming soon
- Mellum2-12B-A2.5B-Thinking public-lane score: 46.3 (Estimated · #81/154)
- Ternary Bonsai 2 27B public-lane score: 49.9 (Estimated · #59/154)

| Benchmark | Mellum2-12B-A2.5B-Thinking | Ternary Bonsai 2 27B | Winner |
|-----------|-----------|-----------|--------|
| BFCL v4 | 45.6% | Coming soon | Coming soon |
| τ²-bench results | Coming soon | 80.2% | Coming soon |
| BFCL v3 | Coming soon | 74.9% | Coming soon |
| Terminal-Bench 2.1 | Coming soon | 52.8% | Coming soon |

### Coding

- Winner: Coming soon
- Mellum2-12B-A2.5B-Thinking public-lane score: Coming soon
- Ternary Bonsai 2 27B public-lane score: 49.9 (Estimated · #64/154)

| Benchmark | Mellum2-12B-A2.5B-Thinking | Ternary Bonsai 2 27B | Winner |
|-----------|-----------|-----------|--------|
| LiveCodeBench v6 | 69.9% | 90.1% | Ternary Bonsai 2 27B |
| BigCodeBench | Coming soon | 58.1% | Coming soon |
| SWE-bench Verified | Coming soon | 60.8% | Coming soon |
| Terminal-Bench 2.1 | Coming soon | 52.8% | Coming soon |

### Multimodal & Grounded

- Winner: Coming soon
- Mellum2-12B-A2.5B-Thinking public-lane score: Coming soon
- Ternary Bonsai 2 27B public-lane score: Coming soon

| Benchmark | Mellum2-12B-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 |

### Reasoning

- Winner: Coming soon
- Mellum2-12B-A2.5B-Thinking public-lane score: Coming soon
- Ternary Bonsai 2 27B public-lane score: 73.9 (Unranked · 1 rankable row)

### Knowledge

- Winner: Coming soon
- Mellum2-12B-A2.5B-Thinking public-lane score: 46.8 (Estimated · #103/184)
- Ternary Bonsai 2 27B public-lane score: 50.6 (Estimated · #78/184)

| Benchmark | Mellum2-12B-A2.5B-Thinking | Ternary Bonsai 2 27B | Winner |
|-----------|-----------|-----------|--------|
| MMLU-Redux | 86.2% | 89.1% | Ternary Bonsai 2 27B |
| GPQA | 57.6% | 85.8% | Ternary Bonsai 2 27B |
| GPQA-D | 57.6% | 85.8% | Ternary Bonsai 2 27B |

### Instruction Following

- Winner: Coming soon
- Mellum2-12B-A2.5B-Thinking public-lane score: Coming soon
- Ternary Bonsai 2 27B public-lane score: 71 (#64/124)

| Benchmark | Mellum2-12B-A2.5B-Thinking | Ternary Bonsai 2 27B | Winner |
|-----------|-----------|-----------|--------|
| IFEval | 76.5% | 91.3% | Ternary Bonsai 2 27B |
| IFBench | Coming soon | 74% | Coming soon |

### Mathematics

- Winner: Coming soon
- Mellum2-12B-A2.5B-Thinking public-lane score: Coming soon
- Ternary Bonsai 2 27B public-lane score: 76.8 (Unranked · 4 rankable rows)

| Benchmark | Mellum2-12B-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, Mellum2-12B-A2.5B-Thinking or Ternary Bonsai 2 27B?

Mellum2-12B-A2.5B-Thinking is ahead overall on BenchLM right now.

### Where is the biggest gap between Mellum2-12B-A2.5B-Thinking and Ternary Bonsai 2 27B?

The widest category gap is in knowledge, where the averages are 46.8 for Mellum2-12B-A2.5B-Thinking and 50.6 for Ternary Bonsai 2 27B.

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

Mellum2-12B-A2.5B-Thinking currently has 6 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

- [Mellum2-12B-A2.5B-Thinking vs Mellum2-12B-A2.5B-Instruct](/compare/mellum2-12b-a2-5b-instruct-vs-mellum2-12b-a2-5b-thinking)
- [Ternary Bonsai 2 27B vs Mellum2-12B-A2.5B-Instruct](/compare/mellum2-12b-a2-5b-instruct-vs-ternary-bonsai-2-27b)
- [Mellum2-12B-A2.5B-Thinking vs Claude Fable 5.1](/compare/claude-fable-5-1-vs-mellum2-12b-a2-5b-thinking)
- [Ternary Bonsai 2 27B vs Claude Fable 5.1](/compare/claude-fable-5-1-vs-ternary-bonsai-2-27b)

## Explore More

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