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Model comparison

GPT-4.1 vs Mellum2-12B-A2.5B-Instruct

Data verified

Head-to-head evidence from 2 shared benchmark results across 2 categories. Overall scores shown here use the public BenchAlign v5 ranking lane.

OpenAI
51.11/100
No comparison
2 category wins0 category wins

Public leaderboard positions: GPT-4.1 #108 (Supported); Mellum2-12B-A2.5B-Instruct 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-Instruct 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-Instruct.

Updated July 23, 2026
Shared results
2
GPT-4.1 only
18
Mellum2-12B-A2.5B-Instruct only
3
Comparable categories
2 / 8

Treat this as a split decision. GPT-4.1 makes more sense if knowledge is the priority or you need the larger 1M context window; Mellum2-12B-A2.5B-Instruct 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 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-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.

GPT-4.1 gives you the larger context window at 1M, 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 scores and score margins for GPT-4.1 and Mellum2-12B-A2.5B-Instruct
CategoryGPT-4.1ΔMellum2-12B-A2.5B-Instruct
KnowledgeGPT-4.166.3Margin 25.4Mellum2-12B-A2.5B-Instruct40.9
Inst. FollowingGPT-4.187.4Margin 11.6Mellum2-12B-A2.5B-Instruct75.8
CodingGPT-4.154.6MarginNo overlapMellum2-12B-A2.5B-InstructNot measured
MathGPT-4.14.1MarginNo overlapMellum2-12B-A2.5B-InstructNot measured

Decisive benchmark drivers

The largest measured benchmark gaps in this matchup, with exact reported values.

More
A · GPT-4.1B · Mellum2-12B-A2.5B-Instruct
  1. GPQA

    Knowledge
    Source ↗
    A 66.3%B 40.9%
    Winner: GPT-4.1Δ 25.4
    GPQA: GPT-4.1 scored 66.3%; Mellum2-12B-A2.5B-Instruct scored 40.9%. GPT-4.1 wins this benchmark.
  2. IFEval

    Inst. Following
    Source ↗
    A 87.4%B 75.8%
    Winner: GPT-4.1Δ 11.6
    IFEval: GPT-4.1 scored 87.4%; Mellum2-12B-A2.5B-Instruct scored 75.8%. GPT-4.1 wins this benchmark.

Operational comparison

Runtime and commercial metrics are compared only when both models have a complete sourced value.

MetricGPT-4.1Mellum2-12B-A2.5B-InstructComparison
Input / output priceUSD per 1M tokensGPT-4.1$2 input / $8 outputMellum2-12B-A2.5B-InstructNot availableA complete price comparison is not available.
Generation speedtokens per secondGPT-4.1108 tok/sMellum2-12B-A2.5B-InstructNot availableA complete speed comparison is not available.
First-answer latencyseconds to first tokenGPT-4.11.02 sMellum2-12B-A2.5B-InstructNot availableA complete latency comparison is not available.
Context windowmaximum listed tokensGPT-4.11MMellum2-12B-A2.5B-Instruct128KGPT-4.1 lists the larger context window.

Benchmark Deep Dive

Agentic
BenchmarkGPT-4.1Mellum2-12B-A2.5B-InstructResult
τ²-bench resultsSource 47.1%Not comparable
Gert LabsSource 25.65%Not comparable
BFCL v4Source 44.2%Not comparable
Coding
BenchmarkGPT-4.1Mellum2-12B-A2.5B-InstructResult
SWE-bench VerifiedSource 54.6%Not comparable
AA-SciCodeSource 38.1%Not comparable
Reasoning
BenchmarkGPT-4.1Mellum2-12B-A2.5B-InstructResult
AA-LCRSource 61.0%Not comparable
CritPtSource 0.0%Not comparable
KnowledgeGPT-4.1 wins
BenchmarkGPT-4.1Mellum2-12B-A2.5B-InstructResult
MMLUSource 90.2%Not comparable
GPQASource 66.3%40.9%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 78.1%Not comparable
GPQA-DSource 40.9%Not comparable
Math
BenchmarkGPT-4.1Mellum2-12B-A2.5B-InstructResult
FrontierMath v2 (Tiers 1-3)Source 5.517%Not comparable
FrontierMath v2 (Tier 4)Source 0.000%Not comparable
Multimodal
BenchmarkGPT-4.1Mellum2-12B-A2.5B-InstructResult
AA-MMMU-ProSource 61.2%Not comparable
Design Arena WebsiteSource 1068Not comparable
Inst. FollowingGPT-4.1 wins
BenchmarkGPT-4.1Mellum2-12B-A2.5B-InstructResult
IFEvalSource 87.4%75.8%GPT-4.1 leads
AA-IFBenchSource 43.0%Not comparable
Frequently Asked Questions (3)

Which is better, GPT-4.1 or Mellum2-12B-A2.5B-Instruct?

GPT-4.1 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, GPT-4.1 or Mellum2-12B-A2.5B-Instruct?

GPT-4.1 has the edge for knowledge tasks in this comparison, averaging 66.3 versus 40.9. 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-Instruct?

GPT-4.1 has the edge for instruction following in this comparison, averaging 87.4 versus 75.8. Inside this category, IFEval is the benchmark that creates the most daylight between them.

Related Comparisons

Last updated: July 23, 2026

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