# DeepSeek V3 vs Mellum2.1-12B-A2.5B-Thinking

> Side-by-side benchmark comparison for DeepSeek V3 and Mellum2.1-12B-A2.5B-Thinking across agentic, coding, multimodal, knowledge, reasoning, multilingual, and math tasks.

- Canonical page: https://benchlm.ai/compare/deepseek-v3-vs-mellum2-1-12b-a2-5b-thinking
- Last updated: October 8, 2026

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

## Quick Verdict

Evidence is too thin for a benchmark verdict: DeepSeek V3 and Mellum2.1-12B-A2.5B-Thinking 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.
- Mellum2.1-12B-A2.5B-Thinking has the lower published output-token price.

## Model Snapshot

| Property | DeepSeek V3 | Mellum2.1-12B-A2.5B-Thinking |
|----------|----------|----------|
| Creator | DeepSeek | JetBrains |
| Type | Open Weight | Open Weight |
| Reasoning | Non-Reasoning | Reasoning |
| Context | 128K | 128K |
| Independent public score (not head-to-head) | 31.92 | null |
| Benchmarks Covered | 6 | 7 |
| Pricing (input/output) | $0.27 / $1.10 | $0.00 / $0.00 |

## Category Breakdown

### Agentic

- Winner: Insufficient shared evidence
- DeepSeek V3 public-lane score: 10.4 (Estimated · #116/122)
- Mellum2.1-12B-A2.5B-Thinking public-lane score: Coming soon

| Benchmark | DeepSeek V3 | Mellum2.1-12B-A2.5B-Thinking | Winner |
|-----------|-----------|-----------|--------|
| Terminal-Bench 2.1 | Coming soon | 17.4% | Coming soon |

### Coding

- Winner: Insufficient shared evidence
- DeepSeek V3 public-lane score: 16.2 (Estimated · #128/146)
- Mellum2.1-12B-A2.5B-Thinking public-lane score: Coming soon

| Benchmark | DeepSeek V3 | Mellum2.1-12B-A2.5B-Thinking | Winner |
|-----------|-----------|-----------|--------|
| LiveCodeBench | 37.6% | Coming soon | Coming soon |
| SWE-bench Verified | 42% | 47% | Mellum2.1-12B-A2.5B-Thinking |
| LiveCodeBench v6 | Coming soon | 82.0% | Coming soon |
| SWE-bench Pro | Coming soon | 28% | Coming soon |

### Reasoning

- Winner: Insufficient shared evidence
- DeepSeek V3 public-lane score: 42.3 (Unranked · 2 rankable rows)
- Mellum2.1-12B-A2.5B-Thinking public-lane score: Coming soon

### Knowledge

- Winner: Insufficient shared evidence
- DeepSeek V3 public-lane score: 30.1 (Estimated · #139/174)
- Mellum2.1-12B-A2.5B-Thinking public-lane score: Coming soon

| Benchmark | DeepSeek V3 | Mellum2.1-12B-A2.5B-Thinking | Winner |
|-----------|-----------|-----------|--------|
| GPQA | 59.1% | Coming soon | Coming soon |
| MMLU-Pro | 75.9% | Coming soon | Coming soon |
| MMLU-Redux | Coming soon | 87.8% | Coming soon |
| GPQA-D | Coming soon | 64.6% | Coming soon |

### Instruction Following

- Winner: Insufficient shared evidence
- DeepSeek V3 public-lane score: 38.2 (#104/125)
- Mellum2.1-12B-A2.5B-Thinking public-lane score: Coming soon

| Benchmark | DeepSeek V3 | Mellum2.1-12B-A2.5B-Thinking | Winner |
|-----------|-----------|-----------|--------|
| IFEval | 86.1% | 90.6% | Mellum2.1-12B-A2.5B-Thinking |

### Mathematics

- Winner: Insufficient shared evidence
- DeepSeek V3 public-lane score: 26 (Unranked · 1 rankable row)
- Mellum2.1-12B-A2.5B-Thinking public-lane score: Coming soon

| Benchmark | DeepSeek V3 | Mellum2.1-12B-A2.5B-Thinking | Winner |
|-----------|-----------|-----------|--------|
| FrontierMath v2 (Tiers 1-3) | 1.724% | Coming soon | Coming soon |

## FAQ

### Is there enough evidence to pick between DeepSeek V3 and Mellum2.1-12B-A2.5B-Thinking?

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

- [DeepSeek V3 vs DeepSeek V3 0324](/compare/deepseek-v3-vs-deepseek-v3-0324)
- [Mellum2.1-12B-A2.5B-Thinking vs DeepSeek V3 0324](/compare/deepseek-v3-0324-vs-mellum2-1-12b-a2-5b-thinking)
- [DeepSeek V3 vs Claude Opus 5.5](/compare/claude-opus-5-5-vs-deepseek-v3)
- [Mellum2.1-12B-A2.5B-Thinking vs Claude Opus 5.5](/compare/claude-opus-5-5-vs-mellum2-1-12b-a2-5b-thinking)

## Explore More

- [DeepSeek V3 profile](/models/deepseek-v3)
- [Mellum2.1-12B-A2.5B-Thinking profile](/models/mellum2-1-12b-a2-5b-thinking)
- [Compare Pricing](/llm-pricing)
- [Alternative Finder](/tools/alternative-finder)
- [LLM Selector](/tools/llm-selector)
- [Overall Rankings](/best/overall)