Model comparison
Gemma 4 12B vs Mellum2-12B-A2.5B-Thinking
Head-to-head evidence from 2 shared benchmark results across 1 category. Overall scores shown here use the public BenchAlign v5 ranking lane.
Public leaderboard positions: Gemma 4 12B #137 (Estimated); Mellum2-12B-A2.5B-Thinking unranked (Not scored). Intervals and evidence labels describe ranking uncertainty, not a guarantee for a specific workload.
Evidence parity. Gemma 4 12B and Mellum2-12B-A2.5B-Thinking share 2 comparable benchmark results. 1 of 8 categories are comparable. 21 results are unique to Gemma 4 12B; 3 to Mellum2-12B-A2.5B-Thinking.
Updated July 23, 2026- Shared results
- 2
- Gemma 4 12B only
- 21
- Mellum2-12B-A2.5B-Thinking only
- 3
- Comparable categories
- 1 / 8
Treat this as a split decision. Gemma 4 12B makes more sense if knowledge is the priority or you need the larger 256K context window; Mellum2-12B-A2.5B-Thinking is the better fit if its strengths line up with your actual workload.
Confidence note. This is a partial-evidence comparison with 2 shared benchmark results across 1 evidence category; 1 of 8 categories currently have scoreable aggregates for both models. Treat the verdict as directional until coverage is more balanced.
Why this result
Gemma 4 12B and Mellum2-12B-A2.5B-Thinking finish on the same BenchAlign overall score, so this is less about a single winner and more about where the edge shows up. The BenchAlign headline says tie; the benchmark table is where the real choice happens.
Gemma 4 12B gives you the larger context window at 256K, compared with 128K for Mellum2-12B-A2.5B-Thinking.
Category breakdown
Exact category averages are shown below. Not measured means BenchLM does not have enough sourced public coverage for that model and category.
| Category | Gemma 4 12B | Δ | Mellum2-12B-A2.5B-Thinking |
|---|---|---|---|
| Knowledge | Gemma 4 12B77.5 | Margin← 19.9 | Mellum2-12B-A2.5B-Thinking57.6 |
| Reasoning | Gemma 4 12B43.4 | MarginNo overlap | Mellum2-12B-A2.5B-ThinkingNot measured |
| Math | Gemma 4 12B77.5 | MarginNo overlap | Mellum2-12B-A2.5B-ThinkingNot measured |
| Multimodal | Gemma 4 12B69.1 | MarginNo overlap | Mellum2-12B-A2.5B-ThinkingNot measured |
| Inst. Following | Gemma 4 12BNot measured | MarginNo overlap | Mellum2-12B-A2.5B-Thinking76.5 |
Decisive benchmark drivers
The largest measured benchmark gaps in this matchup, with exact reported values.
More
- Source ↗
GPQA
KnowledgeA 78.8%B 57.6%Winner: Gemma 4 12BΔ 21.2GPQA: Gemma 4 12B scored 78.8%; Mellum2-12B-A2.5B-Thinking scored 57.6%. Gemma 4 12B wins this benchmark.
Operational comparison
Runtime and commercial metrics are compared only when both models have a complete sourced value.
| Metric | Gemma 4 12B | Mellum2-12B-A2.5B-Thinking | Comparison |
|---|---|---|---|
| Input / output priceUSD per 1M tokens | Gemma 4 12BNot available | Mellum2-12B-A2.5B-ThinkingNot available | A complete price comparison is not available. |
| Generation speedtokens per second | Gemma 4 12BNot available | Mellum2-12B-A2.5B-ThinkingNot available | A complete speed comparison is not available. |
| First-answer latencyseconds to first token | Gemma 4 12BNot available | Mellum2-12B-A2.5B-ThinkingNot available | A complete latency comparison is not available. |
| Context windowmaximum listed tokens | Gemma 4 12B256K | Mellum2-12B-A2.5B-Thinking128K | Gemma 4 12B lists the larger context window. |
Benchmark Deep Dive
Agentic2 benchmarks
Coding1 benchmarks
| Benchmark | Gemma 4 12B | Mellum2-12B-A2.5B-Thinking | Result |
|---|---|---|---|
| AA-SciCodeSource | 38.2% | — | Not comparable |
Reasoning4 benchmarks
KnowledgeGemma 4 12B wins12 benchmarks
| Benchmark | Gemma 4 12B | Mellum2-12B-A2.5B-Thinking | Result |
|---|---|---|---|
| GPQASource | 78.8% | 57.6% | Gemma 4 12B leads |
| GPQA-DSource | 78.8% | 57.6% | Gemma 4 12B leads |
| MMLU-ProSource | 77.2% | — | Not comparable |
| HLE w/o toolsSource | 5.2% | — | Not comparable |
| MMMLUSource | 83.4% | — | Not comparable |
| Artificial Analysis Intelligence IndexSource | 22.0% | — | Not comparable |
| AA-GPQA DiamondSource | 75.3% | — | Not comparable |
| AA-HLESource | 14.8% | — | Not comparable |
| AA-Omniscience IndexSource | -51.9% | — | Not comparable |
| AA-Omniscience AccuracySource | 16.0% | — | Not comparable |
| AA-Omniscience Hallucination RateSource | 80.8% | — | Not comparable |
| MMLU-ReduxSource | — | 86.2% | Not comparable |
Math1 benchmarks
| Benchmark | Gemma 4 12B | Mellum2-12B-A2.5B-Thinking | Result |
|---|---|---|---|
| AIME26Source | 77.5% | — | Not comparable |
Multimodal4 benchmarks
Frequently Asked Questions (2)
Which is better, Gemma 4 12B or Mellum2-12B-A2.5B-Thinking?
Gemma 4 12B and Mellum2-12B-A2.5B-Thinking are tied on the BenchAlign overall score, so the right pick depends on which category matters most for your use case.
Which is better for knowledge tasks, Gemma 4 12B or Mellum2-12B-A2.5B-Thinking?
Gemma 4 12B has the edge for knowledge tasks in this comparison, averaging 77.5 versus 57.6. Inside this category, GPQA is the benchmark that creates the most daylight between them.
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