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Model comparison

Mellum2-12B-A2.5B-Thinking vs Sakana Fugu-Ultra

Data verified

Head-to-head evidence from 2 shared benchmark results across 1 category. Overall scores shown here use the public BenchAlign v5 ranking lane.

N/A
No comparison
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0 category wins1 category wins

Evidence parity. Mellum2-12B-A2.5B-Thinking and Sakana Fugu-Ultra share 2 comparable benchmark results. 1 of 8 categories are comparable. 3 results are unique to Mellum2-12B-A2.5B-Thinking; 9 to Sakana Fugu-Ultra.

Updated July 23, 2026
Shared results
2
Mellum2-12B-A2.5B-Thinking only
3
Sakana Fugu-Ultra only
9
Comparable categories
1 / 8

Treat this as a split decision. Mellum2-12B-A2.5B-Thinking makes more sense if its workflow fits your team better; Sakana Fugu-Ultra is the better fit if knowledge is the priority or you need the larger 1M context window.

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

Mellum2-12B-A2.5B-Thinking and Sakana Fugu-Ultra 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.

Sakana Fugu-Ultra 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 scores and score margins for Mellum2-12B-A2.5B-Thinking and Sakana Fugu-Ultra
CategoryMellum2-12B-A2.5B-ThinkingΔSakana Fugu-Ultra
KnowledgeMellum2-12B-A2.5B-Thinking57.6Margin→ 37.9Sakana Fugu-Ultra95.5
AgenticMellum2-12B-A2.5B-ThinkingNot measuredMarginNo overlapSakana Fugu-Ultra82.1
CodingMellum2-12B-A2.5B-ThinkingNot measuredMarginNo overlapSakana Fugu-Ultra64.5
ReasoningMellum2-12B-A2.5B-ThinkingNot measuredMarginNo overlapSakana Fugu-Ultra93.6
MultimodalMellum2-12B-A2.5B-ThinkingNot measuredMarginNo overlapSakana Fugu-Ultra86.6
Inst. FollowingMellum2-12B-A2.5B-Thinking76.5MarginNo overlapSakana Fugu-UltraNot measured

Decisive benchmark drivers

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

More
A · Mellum2-12B-A2.5B-ThinkingB · Sakana Fugu-Ultra

  1. GPQA

    Knowledge
    Source ↗
    A 57.6%B 95.5%
    Winner: Sakana Fugu-UltraΔ 37.9
    GPQA: Mellum2-12B-A2.5B-Thinking scored 57.6%; Sakana Fugu-Ultra scored 95.5%. Sakana Fugu-Ultra wins this benchmark.

Operational comparison

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

MetricMellum2-12B-A2.5B-ThinkingSakana Fugu-UltraComparison
Input / output priceUSD per 1M tokensMellum2-12B-A2.5B-ThinkingNot availableSakana Fugu-UltraNot availableA complete price comparison is not available.
Generation speedtokens per secondMellum2-12B-A2.5B-ThinkingNot availableSakana Fugu-UltraNot availableA complete speed comparison is not available.
First-answer latencyseconds to first tokenMellum2-12B-A2.5B-ThinkingNot availableSakana Fugu-UltraNot availableA complete latency comparison is not available.
Context windowmaximum listed tokensMellum2-12B-A2.5B-Thinking128KSakana Fugu-Ultra1MSakana Fugu-Ultra lists the larger context window.

Benchmark Deep Dive

Agentic
BenchmarkMellum2-12B-A2.5B-ThinkingSakana Fugu-UltraResult
BFCL v4Source 45.6%—Not comparable
Terminal-Bench 2.0Source —82.1%Not comparable
Coding
BenchmarkMellum2-12B-A2.5B-ThinkingSakana Fugu-UltraResult
SWE-bench ProSource —73.7%Not comparable
Terminal-Bench 2.0Source —82.1%Not comparable
LiveCodeBench v6Source —93.2%Not comparable
LiveCodeBench ProSource —90.8%Not comparable
SciCodeSource —58.7%Not comparable
Reasoning
BenchmarkMellum2-12B-A2.5B-ThinkingSakana Fugu-UltraResult
MRCRv2Source —93.6%Not comparable
KnowledgeSakana Fugu-Ultra wins
BenchmarkMellum2-12B-A2.5B-ThinkingSakana Fugu-UltraResult
MMLU-ReduxSource 86.2%—Not comparable
GPQASource 57.6%95.5%Sakana Fugu-Ultra leads
GPQA-DSource 57.6%95.5%Sakana Fugu-Ultra leads
HLE w/o toolsSource —50%Not comparable
Multimodal
BenchmarkMellum2-12B-A2.5B-ThinkingSakana Fugu-UltraResult
CharXivSource —86.6%Not comparable
Inst. Following
BenchmarkMellum2-12B-A2.5B-ThinkingSakana Fugu-UltraResult
IFEvalSource 76.5%—Not comparable
Frequently Asked Questions (2)

Which is better, Mellum2-12B-A2.5B-Thinking or Sakana Fugu-Ultra?

Mellum2-12B-A2.5B-Thinking and Sakana Fugu-Ultra 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, Mellum2-12B-A2.5B-Thinking or Sakana Fugu-Ultra?

Sakana Fugu-Ultra has the edge for knowledge tasks in this comparison, averaging 95.5 versus 57.6. Inside this category, GPQA is the benchmark that creates the most daylight between them.

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