Model comparison
Gemma 4 12B vs Mellum2-12B-A2.5B-Instruct
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-Instruct 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-Instruct 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-Instruct.
Updated July 23, 2026- Shared results
- 2
- Gemma 4 12B only
- 21
- Mellum2-12B-A2.5B-Instruct 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-Instruct is the better fit if you would rather avoid the extra latency and token burn of a reasoning model.
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-Instruct 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 is the reasoning model in the pair, while Mellum2-12B-A2.5B-Instruct is not. That usually helps on harder chain-of-thought-heavy tests, but it can also mean more latency and more token spend in real use. Gemma 4 12B gives you the larger context window at 256K, compared with 128K for Mellum2-12B-A2.5B-Instruct.
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-Instruct |
|---|---|---|---|
| Knowledge | Gemma 4 12B77.5 | Margin← 36.6 | Mellum2-12B-A2.5B-Instruct40.9 |
| Reasoning | Gemma 4 12B43.4 | MarginNo overlap | Mellum2-12B-A2.5B-InstructNot measured |
| Math | Gemma 4 12B77.5 | MarginNo overlap | Mellum2-12B-A2.5B-InstructNot measured |
| Multimodal | Gemma 4 12B69.1 | MarginNo overlap | Mellum2-12B-A2.5B-InstructNot measured |
| Inst. Following | Gemma 4 12BNot measured | MarginNo overlap | Mellum2-12B-A2.5B-Instruct75.8 |
Decisive benchmark drivers
The largest measured benchmark gaps in this matchup, with exact reported values.
More
- Source ↗
GPQA
KnowledgeA 78.8%B 40.9%Winner: Gemma 4 12BΔ 37.9GPQA: Gemma 4 12B scored 78.8%; Mellum2-12B-A2.5B-Instruct scored 40.9%. 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-Instruct | Comparison |
|---|---|---|---|
| Input / output priceUSD per 1M tokens | Gemma 4 12BNot available | Mellum2-12B-A2.5B-InstructNot available | A complete price comparison is not available. |
| Generation speedtokens per second | Gemma 4 12BNot available | Mellum2-12B-A2.5B-InstructNot available | A complete speed comparison is not available. |
| First-answer latencyseconds to first token | Gemma 4 12BNot available | Mellum2-12B-A2.5B-InstructNot available | A complete latency comparison is not available. |
| Context windowmaximum listed tokens | Gemma 4 12B256K | Mellum2-12B-A2.5B-Instruct128K | Gemma 4 12B lists the larger context window. |
Benchmark Deep Dive
Agentic2 benchmarks
Coding1 benchmarks
| Benchmark | Gemma 4 12B | Mellum2-12B-A2.5B-Instruct | Result |
|---|---|---|---|
| AA-SciCodeSource | 38.2% | — | Not comparable |
Reasoning4 benchmarks
KnowledgeGemma 4 12B wins12 benchmarks
| Benchmark | Gemma 4 12B | Mellum2-12B-A2.5B-Instruct | Result |
|---|---|---|---|
| GPQASource | 78.8% | 40.9% | Gemma 4 12B leads |
| GPQA-DSource | 78.8% | 40.9% | 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 | — | 78.1% | Not comparable |
Math1 benchmarks
| Benchmark | Gemma 4 12B | Mellum2-12B-A2.5B-Instruct | Result |
|---|---|---|---|
| AIME26Source | 77.5% | — | Not comparable |
Multimodal4 benchmarks
Frequently Asked Questions (2)
Which is better, Gemma 4 12B or Mellum2-12B-A2.5B-Instruct?
Gemma 4 12B and Mellum2-12B-A2.5B-Instruct 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-Instruct?
Gemma 4 12B has the edge for knowledge tasks in this comparison, averaging 77.5 versus 40.9. Inside this category, GPQA is the benchmark that creates the most daylight between them.
Related Comparisons
Explore More
Choose a model with this week’s evidence
Join 2,000+ readers for ranking moves, pricing changes, and the claims that still need proof.
One email each week. Unsubscribe anytime.