Model comparison
Kimi K2.5 vs Sakana Fugu-Ultra
Head-to-head evidence from 6 shared benchmark results across 3 categories. Overall scores shown here use the public BenchAlign v5 ranking lane.
Public leaderboard positions: Kimi K2.5 #54 (Supported); Sakana Fugu-Ultra unranked (Not scored). Intervals and evidence labels describe ranking uncertainty, not a guarantee for a specific workload.
Evidence parity. Kimi K2.5 and Sakana Fugu-Ultra share 6 comparable benchmark results. 5 of 8 categories are comparable. 57 results are unique to Kimi K2.5; 5 to Sakana Fugu-Ultra.
Updated July 23, 2026- Shared results
- 6
- Kimi K2.5 only
- 57
- Sakana Fugu-Ultra only
- 5
- Comparable categories
- 5 / 8
Treat this as a split decision. Kimi K2.5 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 6 shared benchmark results across 3 evidence categories; 5 of 8 categories currently have scoreable aggregates for both models. Treat the verdict as directional until coverage is more balanced.
Why this result
Kimi K2.5 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 Kimi K2.5 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 256K for Kimi K2.5.
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 | Kimi K2.5 | Δ | Sakana Fugu-Ultra |
|---|---|---|---|
| Knowledge | Kimi K2.556.9 | Margin→ 38.6 | Sakana Fugu-Ultra95.5 |
| Reasoning | Kimi K2.561.0 | Margin→ 32.6 | Sakana Fugu-Ultra93.6 |
| Agentic | Kimi K2.555.0 | Margin→ 27.1 | Sakana Fugu-Ultra82.1 |
| Multimodal | Kimi K2.578.5 | Margin→ 8.1 | Sakana Fugu-Ultra86.6 |
| Coding | Kimi K2.559.4 | Margin→ 5.1 | Sakana Fugu-Ultra64.5 |
| Math | Kimi K2.560.6 | MarginNo overlap | Sakana Fugu-UltraNot measured |
| Multilingual | Kimi K2.582.3 | MarginNo overlap | Sakana Fugu-UltraNot measured |
| Inst. Following | Kimi K2.593.9 | MarginNo overlap | Sakana Fugu-UltraNot measured |
Decisive benchmark drivers
The largest measured benchmark gaps in this matchup, with exact reported values.
More
- Source ↗
Terminal-Bench 2.0
AgenticA 50.8%B 82.1%Winner: Sakana Fugu-UltraΔ 31.3Terminal-Bench 2.0: Kimi K2.5 scored 50.8%; Sakana Fugu-Ultra scored 82.1%. Sakana Fugu-Ultra wins this benchmark. - Source ↗
SWE-bench Pro
CodingA 50.7%B 73.7%Winner: Sakana Fugu-UltraΔ 23SWE-bench Pro: Kimi K2.5 scored 50.7%; Sakana Fugu-Ultra scored 73.7%. Sakana Fugu-Ultra wins this benchmark. - Source ↗
SciCode
CodingA 48.7%B 58.7%Winner: Sakana Fugu-UltraΔ 10SciCode: Kimi K2.5 scored 48.7%; Sakana Fugu-Ultra scored 58.7%. Sakana Fugu-Ultra wins this benchmark. - Source ↗
GPQA
KnowledgeA 87.6%B 95.5%Winner: Sakana Fugu-UltraΔ 7.9GPQA: Kimi K2.5 scored 87.6%; 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.
| Metric | Kimi K2.5 | Sakana Fugu-Ultra | Comparison |
|---|---|---|---|
| Input / output priceUSD per 1M tokens | Kimi K2.5$0.6 input / $3 output | Sakana Fugu-UltraNot available | A complete price comparison is not available. |
| Generation speedtokens per second | Kimi K2.545 tok/s | Sakana Fugu-UltraNot available | A complete speed comparison is not available. |
| First-answer latencyseconds to first token | Kimi K2.52.38 s | Sakana Fugu-UltraNot available | A complete latency comparison is not available. |
| Context windowmaximum listed tokens | Kimi K2.5256K | Sakana Fugu-Ultra1M | Sakana Fugu-Ultra lists the larger context window. |
Benchmark Deep Dive
AgenticSakana Fugu-Ultra wins19 benchmarks
| Benchmark | Kimi K2.5 | Sakana Fugu-Ultra | Result |
|---|---|---|---|
| Terminal-Bench 2.0Source | 50.8% | 82.1% | Sakana Fugu-Ultra leads |
| BrowseCompSource | 60.6% | — | Not comparable |
| Claw-EvalSource | 52.3% | — | Not comparable |
| QwenClawBenchSource | 54.3% | — | Not comparable |
| τ³-bench resultsSource | 65.7% | — | Not comparable |
| DeepSearchQASource | 77.1% | — | Not comparable |
| DeepPlanningSource | 14.4% | — | Not comparable |
| ToolathlonSource | 27.8% | — | Not comparable |
| MCP AtlasSource | 29.5% | — | Not comparable |
| MCP-TasksSource | 59.1% | — | Not comparable |
| WideResearchSource | 72.7% | — | Not comparable |
| τ²-bench resultsSource | 95.9% | — | Not comparable |
| APEX-Agents-AASource | 11.5% | — | Not comparable |
| Gert LabsSource | 45.88% | — | Not comparable |
| ResearchClawBenchSource | 14.0% | — | Not comparable |
| JobBenchSource | 8.7% | — | Not comparable |
| AA Agentic IndexSource | 21.7% | — | Not comparable |
| GDPval-AASource | 25.4% | — | Not comparable |
| GDPval-AASource | 1009 | — | Not comparable |
CodingSakana Fugu-Ultra wins12 benchmarks
| Benchmark | Kimi K2.5 | Sakana Fugu-Ultra | Result |
|---|---|---|---|
| SWE-bench VerifiedSource | 76.8% | — | Not comparable |
| SWE-bench Verified*Source | 70.8% | — | Not comparable |
| LiveCodeBench v6Source | 85.0% | 93.2% | Sakana Fugu-Ultra leads |
| SWE-bench ProSource | 50.7% | 73.7% | Sakana Fugu-Ultra leads |
| SWE MultilingualSource | 73% | — | Not comparable |
| SWE-RebenchSource | 58.5% | — | Not comparable |
| React Native EvalsSource | 77.2% | — | Not comparable |
| SciCodeSource | 48.7% | 58.7% | Sakana Fugu-Ultra leads |
| AA-SciCodeSource | 49.0% | — | Not comparable |
| AA Coding IndexSource | 46.8% | — | Not comparable |
| Terminal-Bench 2.0Source | — | 82.1% | Not comparable |
| LiveCodeBench ProSource | — | 90.8% | Not comparable |
ReasoningSakana Fugu-Ultra wins4 benchmarks
KnowledgeSakana Fugu-Ultra wins13 benchmarks
| Benchmark | Kimi K2.5 | Sakana Fugu-Ultra | Result |
|---|---|---|---|
| GPQASource | 87.6% | 95.5% | Sakana Fugu-Ultra leads |
| GPQA-DSource | 87.6% | 95.5% | Sakana Fugu-Ultra leads |
| SuperGPQASource | 69.2% | — | Not comparable |
| MMLU-ProSource | 87.1% | — | Not comparable |
| MMLU-Pro (Arcee)Source | 87.1% | — | Not comparable |
| HLESource | 30.1% | — | Not comparable |
| Artificial Analysis Intelligence IndexSource | 35.4% | — | Not comparable |
| AA-GPQA DiamondSource | 87.9% | — | Not comparable |
| AA-HLESource | 29.4% | — | Not comparable |
| AA-Omniscience IndexSource | -8.1% | — | Not comparable |
| AA-Omniscience AccuracySource | 34.3% | — | Not comparable |
| AA-Omniscience Hallucination RateSource | 64.6% | — | Not comparable |
| HLE w/o toolsSource | — | 50% | Not comparable |
Math9 benchmarks
| Benchmark | Kimi K2.5 | Sakana Fugu-Ultra | Result |
|---|---|---|---|
| AIME 2025Source | 96.1% | — | Not comparable |
| AIME26Source | 95.8% | — | Not comparable |
| AIME25 (Arcee)Source | 96.3% | — | Not comparable |
| HMMT Feb 2025Source | 95.4% | — | Not comparable |
| HMMT Nov 2025Source | 91.1% | — | Not comparable |
| HMMT Feb 2026Source | 87.1% | — | Not comparable |
| MMAnswerBenchSource | 81.8% | — | Not comparable |
| FrontierMath v2 (Tiers 1-3)Source | 27.900% | — | Not comparable |
| FrontierMath v2 (Tier 4)Source | 4.200% | — | Not comparable |
Multilingual2 benchmarks
MultimodalSakana Fugu-Ultra wins7 benchmarks
Frequently Asked Questions (6)
Which is better, Kimi K2.5 or Sakana Fugu-Ultra?
Kimi K2.5 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, Kimi K2.5 or Sakana Fugu-Ultra?
Sakana Fugu-Ultra has the edge for knowledge tasks in this comparison, averaging 95.5 versus 56.9. Inside this category, GPQA is the benchmark that creates the most daylight between them.
Which is better for coding, Kimi K2.5 or Sakana Fugu-Ultra?
Sakana Fugu-Ultra has the edge for coding in this comparison, averaging 64.5 versus 59.4. Inside this category, SWE-bench Pro is the benchmark that creates the most daylight between them.
Which is better for reasoning, Kimi K2.5 or Sakana Fugu-Ultra?
Sakana Fugu-Ultra has the edge for reasoning in this comparison, averaging 93.6 versus 61. Kimi K2.5 stays close enough that the answer can still flip depending on your workload.
Which is better for agentic tasks, Kimi K2.5 or Sakana Fugu-Ultra?
Sakana Fugu-Ultra has the edge for agentic tasks in this comparison, averaging 82.1 versus 55. Inside this category, Terminal-Bench 2.0 is the benchmark that creates the most daylight between them.
Which is better for multimodal and grounded tasks, Kimi K2.5 or Sakana Fugu-Ultra?
Sakana Fugu-Ultra has the edge for multimodal and grounded tasks in this comparison, averaging 86.6 versus 78.5. Kimi K2.5 stays close enough that the answer can still flip depending on your workload.
Self-host vs API cost
Estimates at 50,000 req/day · 1000 tokens/req average.
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