Model comparison
Mellum2-12B-A2.5B-Instruct vs Sakana Fugu-Ultra
Head-to-head evidence from 2 shared benchmark results across 1 category. Overall scores shown here use the public BenchAlign v5 ranking lane.
Evidence parity. Mellum2-12B-A2.5B-Instruct and Sakana Fugu-Ultra share 2 comparable benchmark results. 1 of 8 categories are comparable. 3 results are unique to Mellum2-12B-A2.5B-Instruct; 9 to Sakana Fugu-Ultra.
Updated July 23, 2026- Shared results
- 2
- Mellum2-12B-A2.5B-Instruct only
- 3
- Sakana Fugu-Ultra only
- 9
- Comparable categories
- 1 / 8
Treat this as a split decision. Mellum2-12B-A2.5B-Instruct makes more sense if you would rather avoid the extra latency and token burn of a reasoning model; 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-Instruct 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 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. Sakana Fugu-Ultra 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 | Mellum2-12B-A2.5B-Instruct | Δ | Sakana Fugu-Ultra |
|---|---|---|---|
| Knowledge | Mellum2-12B-A2.5B-Instruct40.9 | Margin→ 54.6 | Sakana Fugu-Ultra95.5 |
| Agentic | Mellum2-12B-A2.5B-InstructNot measured | MarginNo overlap | Sakana Fugu-Ultra82.1 |
| Coding | Mellum2-12B-A2.5B-InstructNot measured | MarginNo overlap | Sakana Fugu-Ultra64.5 |
| Reasoning | Mellum2-12B-A2.5B-InstructNot measured | MarginNo overlap | Sakana Fugu-Ultra93.6 |
| Multimodal | Mellum2-12B-A2.5B-InstructNot measured | MarginNo overlap | Sakana Fugu-Ultra86.6 |
| Inst. Following | Mellum2-12B-A2.5B-Instruct75.8 | MarginNo overlap | Sakana Fugu-UltraNot measured |
Decisive benchmark drivers
The largest measured benchmark gaps in this matchup, with exact reported values.
More
- Source ↗
GPQA
KnowledgeA 40.9%B 95.5%Winner: Sakana Fugu-UltraΔ 54.6GPQA: Mellum2-12B-A2.5B-Instruct scored 40.9%; 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.
| Metric | Mellum2-12B-A2.5B-Instruct | Sakana Fugu-Ultra | Comparison |
|---|---|---|---|
| Input / output priceUSD per 1M tokens | Mellum2-12B-A2.5B-InstructNot available | Sakana Fugu-UltraNot available | A complete price comparison is not available. |
| Generation speedtokens per second | Mellum2-12B-A2.5B-InstructNot available | Sakana Fugu-UltraNot available | A complete speed comparison is not available. |
| First-answer latencyseconds to first token | Mellum2-12B-A2.5B-InstructNot available | Sakana Fugu-UltraNot available | A complete latency comparison is not available. |
| Context windowmaximum listed tokens | Mellum2-12B-A2.5B-Instruct128K | Sakana Fugu-Ultra1M | Sakana Fugu-Ultra lists the larger context window. |
Benchmark Deep Dive
Agentic2 benchmarks
Coding5 benchmarks
Reasoning1 benchmarks
| Benchmark | Mellum2-12B-A2.5B-Instruct | Sakana Fugu-Ultra | Result |
|---|---|---|---|
| MRCRv2Source | — | 93.6% | Not comparable |
KnowledgeSakana Fugu-Ultra wins4 benchmarks
Multimodal1 benchmarks
| Benchmark | Mellum2-12B-A2.5B-Instruct | Sakana Fugu-Ultra | Result |
|---|---|---|---|
| CharXivSource | — | 86.6% | Not comparable |
Inst. Following1 benchmarks
| Benchmark | Mellum2-12B-A2.5B-Instruct | Sakana Fugu-Ultra | Result |
|---|---|---|---|
| IFEvalSource | 75.8% | — | Not comparable |
Frequently Asked Questions (2)
Which is better, Mellum2-12B-A2.5B-Instruct or Sakana Fugu-Ultra?
Mellum2-12B-A2.5B-Instruct 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-Instruct or Sakana Fugu-Ultra?
Sakana Fugu-Ultra has the edge for knowledge tasks in this comparison, averaging 95.5 versus 40.9. Inside this category, GPQA is the benchmark that creates the most daylight between them.
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