Model comparison
GPT-4.1 vs Mellum2-12B-A2.5B-Thinking
Head-to-head evidence from 2 shared benchmark results across 2 categories. Overall scores shown here use the public BenchAlign v5 ranking lane.
Public leaderboard positions: GPT-4.1 #108 (Supported); Mellum2-12B-A2.5B-Thinking unranked (Not scored). Intervals and evidence labels describe ranking uncertainty, not a guarantee for a specific workload.
Evidence parity. GPT-4.1 and Mellum2-12B-A2.5B-Thinking share 2 comparable benchmark results. 2 of 8 categories are comparable. 18 results are unique to GPT-4.1; 3 to Mellum2-12B-A2.5B-Thinking.
Updated July 23, 2026- Shared results
- 2
- GPT-4.1 only
- 18
- Mellum2-12B-A2.5B-Thinking only
- 3
- Comparable categories
- 2 / 8
Treat this as a split decision. GPT-4.1 makes more sense if instruction following is the priority or you need the larger 1M context window; Mellum2-12B-A2.5B-Thinking is the better fit if you want the stronger reasoning-first profile.
Confidence note. This is a partial-evidence comparison with 2 shared benchmark results across 2 evidence categories; 2 of 8 categories currently have scoreable aggregates for both models. Treat the verdict as directional until coverage is more balanced.
Why this result
GPT-4.1 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.
Mellum2-12B-A2.5B-Thinking is the reasoning model in the pair, while GPT-4.1 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. GPT-4.1 gives you the larger context window at 1M, 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 | GPT-4.1 | Δ | Mellum2-12B-A2.5B-Thinking |
|---|---|---|---|
| Inst. Following | GPT-4.187.4 | Margin← 10.9 | Mellum2-12B-A2.5B-Thinking76.5 |
| Knowledge | GPT-4.166.3 | Margin← 8.7 | Mellum2-12B-A2.5B-Thinking57.6 |
| Coding | GPT-4.154.6 | MarginNo overlap | Mellum2-12B-A2.5B-ThinkingNot measured |
| Math | GPT-4.14.1 | MarginNo overlap | Mellum2-12B-A2.5B-ThinkingNot measured |
Decisive benchmark drivers
The largest measured benchmark gaps in this matchup, with exact reported values.
More
- Source ↗
IFEval
Inst. FollowingA 87.4%B 76.5%Winner: GPT-4.1Δ 10.9IFEval: GPT-4.1 scored 87.4%; Mellum2-12B-A2.5B-Thinking scored 76.5%. GPT-4.1 wins this benchmark. - Source ↗
GPQA
KnowledgeA 66.3%B 57.6%Winner: GPT-4.1Δ 8.7GPQA: GPT-4.1 scored 66.3%; Mellum2-12B-A2.5B-Thinking scored 57.6%. GPT-4.1 wins this benchmark.
Operational comparison
Runtime and commercial metrics are compared only when both models have a complete sourced value.
| Metric | GPT-4.1 | Mellum2-12B-A2.5B-Thinking | Comparison |
|---|---|---|---|
| Input / output priceUSD per 1M tokens | GPT-4.1$2 input / $8 output | Mellum2-12B-A2.5B-ThinkingNot available | A complete price comparison is not available. |
| Generation speedtokens per second | GPT-4.1108 tok/s | Mellum2-12B-A2.5B-ThinkingNot available | A complete speed comparison is not available. |
| First-answer latencyseconds to first token | GPT-4.11.02 s | Mellum2-12B-A2.5B-ThinkingNot available | A complete latency comparison is not available. |
| Context windowmaximum listed tokens | GPT-4.11M | Mellum2-12B-A2.5B-Thinking128K | GPT-4.1 lists the larger context window. |
Benchmark Deep Dive
Agentic3 benchmarks
Coding2 benchmarks
Reasoning2 benchmarks
KnowledgeGPT-4.1 wins10 benchmarks
| Benchmark | GPT-4.1 | Mellum2-12B-A2.5B-Thinking | Result |
|---|---|---|---|
| MMLUSource | 90.2% | — | Not comparable |
| GPQASource | 66.3% | 57.6% | GPT-4.1 leads |
| Artificial Analysis Intelligence IndexSource | 19.4% | — | Not comparable |
| AA-GPQA DiamondSource | 66.6% | — | Not comparable |
| AA-HLESource | 4.6% | — | Not comparable |
| AA-Omniscience IndexSource | -36.2% | — | Not comparable |
| AA-Omniscience AccuracySource | 24.2% | — | Not comparable |
| AA-Omniscience Hallucination RateSource | 79.6% | — | Not comparable |
| MMLU-ReduxSource | — | 86.2% | Not comparable |
| GPQA-DSource | — | 57.6% | Not comparable |
Math2 benchmarks
Multimodal2 benchmarks
Frequently Asked Questions (3)
Which is better, GPT-4.1 or Mellum2-12B-A2.5B-Thinking?
GPT-4.1 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, GPT-4.1 or Mellum2-12B-A2.5B-Thinking?
GPT-4.1 has the edge for knowledge tasks in this comparison, averaging 66.3 versus 57.6. Inside this category, GPQA is the benchmark that creates the most daylight between them.
Which is better for instruction following, GPT-4.1 or Mellum2-12B-A2.5B-Thinking?
GPT-4.1 has the edge for instruction following in this comparison, averaging 87.4 versus 76.5. Inside this category, IFEval is the benchmark that creates the most daylight between them.
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