# Mellum2-12B-A2.5B-Instruct vs Mellum2-12B-A2.5B-Thinking

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

- Canonical page: https://benchlm.ai/compare/mellum2-12b-a2-5b-instruct-vs-mellum2-12b-a2-5b-thinking
- Last updated: September 4, 2026

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

## Quick Verdict

Pick Mellum2-12B-A2.5B-Thinking if you want the stronger benchmark profile. Mellum2-12B-A2.5B-Instruct 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 43.
- The clearest category separation is in knowledge, where the averages are 48.1 for Mellum2-12B-A2.5B-Instruct and 48.8 for Mellum2-12B-A2.5B-Thinking.
- The biggest single benchmark swing is LiveCodeBench v6 in Coding, with scores of 37.2% and 69.9%.

## Model Snapshot

| Property | Mellum2-12B-A2.5B-Instruct | Mellum2-12B-A2.5B-Thinking |
|----------|----------|----------|
| Creator | JetBrains | JetBrains |
| Type | Open Weight | Open Weight |
| Reasoning | Non-Reasoning | Reasoning |
| Context | 128K | 128K |
| Overall Score | null | null |
| Benchmarks Covered | 6 | 6 |
| Pricing (input/output) | N/A | N/A |

## Category Breakdown

### Agentic

- Winner: Coming soon
- Mellum2-12B-A2.5B-Instruct public-lane score: 47.8 (Estimated · #82/151)
- Mellum2-12B-A2.5B-Thinking public-lane score: 48.3 (Estimated · #76/151)

| Benchmark | Mellum2-12B-A2.5B-Instruct | Mellum2-12B-A2.5B-Thinking | Winner |
|-----------|-----------|-----------|--------|
| BFCL v4 | 44.2% | 45.6% | Mellum2-12B-A2.5B-Thinking |

### Coding

- Winner: Coming soon
- Mellum2-12B-A2.5B-Instruct public-lane score: Coming soon
- Mellum2-12B-A2.5B-Thinking public-lane score: Coming soon

| Benchmark | Mellum2-12B-A2.5B-Instruct | Mellum2-12B-A2.5B-Thinking | Winner |
|-----------|-----------|-----------|--------|
| LiveCodeBench v6 | 37.2% | 69.9% | Mellum2-12B-A2.5B-Thinking |

### Knowledge

- Winner: Coming soon
- Mellum2-12B-A2.5B-Instruct public-lane score: 48.1 (Estimated · #103/181)
- Mellum2-12B-A2.5B-Thinking public-lane score: 48.8 (Estimated · #96/181)

| Benchmark | Mellum2-12B-A2.5B-Instruct | Mellum2-12B-A2.5B-Thinking | Winner |
|-----------|-----------|-----------|--------|
| MMLU-Redux | 78.1% | 86.2% | Mellum2-12B-A2.5B-Thinking |
| GPQA | 40.9% | 57.6% | Mellum2-12B-A2.5B-Thinking |
| GPQA-D | 40.9% | 57.6% | Mellum2-12B-A2.5B-Thinking |

### Instruction Following

- Winner: Coming soon
- Mellum2-12B-A2.5B-Instruct public-lane score: Coming soon
- Mellum2-12B-A2.5B-Thinking public-lane score: Coming soon

| Benchmark | Mellum2-12B-A2.5B-Instruct | Mellum2-12B-A2.5B-Thinking | Winner |
|-----------|-----------|-----------|--------|
| IFEval | 75.8% | 76.5% | Mellum2-12B-A2.5B-Thinking |

## FAQ

### Which is better overall, Mellum2-12B-A2.5B-Instruct or Mellum2-12B-A2.5B-Thinking?

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

### Where is the biggest gap between Mellum2-12B-A2.5B-Instruct and Mellum2-12B-A2.5B-Thinking?

The widest category gap is in knowledge, where the averages are 48.1 for Mellum2-12B-A2.5B-Instruct and 48.8 for Mellum2-12B-A2.5B-Thinking.

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

Mellum2-12B-A2.5B-Instruct currently has 6 sourced benchmark scores on BenchLM.

### 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.

## Related Comparisons

- [Mellum2-12B-A2.5B-Instruct vs Claude Fable 5.1](/compare/claude-fable-5-1-vs-mellum2-12b-a2-5b-instruct)
- [Mellum2-12B-A2.5B-Thinking vs Claude Fable 5.1](/compare/claude-fable-5-1-vs-mellum2-12b-a2-5b-thinking)
- [Mellum2-12B-A2.5B-Instruct vs GPT-6 Astra](/compare/gpt-6-astra-vs-mellum2-12b-a2-5b-instruct)
- [Mellum2-12B-A2.5B-Thinking vs GPT-6 Astra](/compare/gpt-6-astra-vs-mellum2-12b-a2-5b-thinking)

## Explore More

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