Model comparison
GPT-5.6 Sol vs Kimi K2.5 (Reasoning)
Head-to-head evidence from 20 shared benchmark results across 6 categories. Overall scores shown here use the public BenchAlign v5 ranking lane.
Public leaderboard positions: GPT-5.6 Sol #3 (Supported); Kimi K2.5 (Reasoning) #57 (Estimated). Intervals and evidence labels describe ranking uncertainty, not a guarantee for a specific workload.
Evidence parity. GPT-5.6 Sol and Kimi K2.5 (Reasoning) share 20 comparable benchmark results. 4 of 8 categories are comparable. 26 results are unique to GPT-5.6 Sol; 7 to Kimi K2.5 (Reasoning).
Updated July 23, 2026- Shared results
- 20
- GPT-5.6 Sol only
- 26
- Kimi K2.5 (Reasoning) only
- 7
- Comparable categories
- 4 / 8
Pick GPT-5.6 Sol if you want the stronger benchmark profile. Kimi K2.5 (Reasoning) only becomes the better choice if coding is the priority or you want the cheaper token bill.
Confidence note. This is a partial-evidence comparison with 20 shared benchmark results across 6 evidence categories; 4 of 8 categories currently have scoreable aggregates for both models. Treat the verdict as directional until coverage is more balanced.
Why this result
GPT-5.6 Sol is clearly ahead on the BenchAlign aggregate, 81.96 to 59.35. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.
GPT-5.6 Sol's sharpest advantage is in agentic, where it averages 92 against 55. The single biggest benchmark swing on the page is Terminal-Bench 2.0, 91.9% to 50.8%. Kimi K2.5 (Reasoning) does hit back in coding, so the answer changes if that is the part of the workload you care about most.
GPT-5.6 Sol is also the more expensive model on tokens at $5.00 input / $30.00 output per 1M tokens, versus $0.60 input / $3.00 output per 1M tokens for Kimi K2.5 (Reasoning). That is roughly 10.0x on output cost alone. GPT-5.6 Sol gives you the larger context window at 1M, compared with 128K for Kimi K2.5 (Reasoning).
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-5.6 Sol | Δ | Kimi K2.5 (Reasoning) |
|---|---|---|---|
| Agentic | GPT-5.6 Sol92.0 | Margin← 37.0 | Kimi K2.5 (Reasoning)55.0 |
| Coding | GPT-5.6 Sol64.6 | Margin→ 12.2 | Kimi K2.5 (Reasoning)76.8 |
| Knowledge | GPT-5.6 Sol94.6 | Margin← 7.4 | Kimi K2.5 (Reasoning)87.2 |
| Multimodal | GPT-5.6 Sol83.0 | Margin← 4.5 | Kimi K2.5 (Reasoning)78.5 |
| Math | GPT-5.6 Sol87.5 | MarginNo overlap | Kimi K2.5 (Reasoning)Not measured |
Decisive benchmark drivers
The largest measured benchmark gaps in this matchup, with exact reported values.
More
- Source ↗
Terminal-Bench 2.0
AgenticA 91.9%B 50.8%Winner: GPT-5.6 SolΔ 41.1Terminal-Bench 2.0: GPT-5.6 Sol scored 91.9%; Kimi K2.5 (Reasoning) scored 50.8%. GPT-5.6 Sol wins this benchmark. - Source ↗
BrowseComp
AgenticA 92.2%B 60.6%Winner: GPT-5.6 SolΔ 31.6BrowseComp: GPT-5.6 Sol scored 92.2%; Kimi K2.5 (Reasoning) scored 60.6%. GPT-5.6 Sol wins this benchmark. - Source ↗
GPQA
KnowledgeA 94.6%B 87.6%Winner: GPT-5.6 SolΔ 7GPQA: GPT-5.6 Sol scored 94.6%; Kimi K2.5 (Reasoning) scored 87.6%. GPT-5.6 Sol wins this benchmark. - Source ↗
MMMU-Pro
MultimodalA 83%B 78.5%Winner: GPT-5.6 SolΔ 4.5MMMU-Pro: GPT-5.6 Sol scored 83%; Kimi K2.5 (Reasoning) scored 78.5%. GPT-5.6 Sol wins this benchmark.
Operational comparison
Runtime and commercial metrics are compared only when both models have a complete sourced value.
| Metric | GPT-5.6 Sol | Kimi K2.5 (Reasoning) | Comparison |
|---|---|---|---|
| Input / output priceUSD per 1M tokens | GPT-5.6 Sol$5 input / $30 output | Kimi K2.5 (Reasoning)$0.6 input / $3 output | Kimi K2.5 (Reasoning) has the lower combined listed price. |
| Generation speedtokens per second | GPT-5.6 SolNot available | Kimi K2.5 (Reasoning)Not available | A complete speed comparison is not available. |
| First-answer latencyseconds to first token | GPT-5.6 SolNot available | Kimi K2.5 (Reasoning)Not available | A complete latency comparison is not available. |
| Context windowmaximum listed tokens | GPT-5.6 Sol1M | Kimi K2.5 (Reasoning)128K | GPT-5.6 Sol lists the larger context window. |
Benchmark Deep Dive
AgenticGPT-5.6 Sol wins19 benchmarks
| Benchmark | GPT-5.6 Sol | Kimi K2.5 (Reasoning) | Result |
|---|---|---|---|
| Terminal-Bench 2.0Source | 91.9% | 50.8% | GPT-5.6 Sol leads |
| BrowseCompSource | 92.2% | 60.6% | GPT-5.6 Sol leads |
| OSWorld 2.0Source | 62.6% | — | Not comparable |
| CyberGymSource | 84.5% | — | Not comparable |
| ExploitGymSource | 33.7% | — | Not comparable |
| ToolathlonSource | 58% | — | Not comparable |
| AA Agentic IndexSource | 54.0% | 21.7% | GPT-5.6 Sol leads |
| τ²-bench resultsSource | 85.1% | 95.9% | Kimi K2.5 (Reasoning) leads |
| GDPval-AASource | 61.8% | 25.4% | GPT-5.6 Sol leads |
| GDPval-AASource | 1736 | 1009 | GPT-5.6 Sol leads |
| AA BriefcaseSource | 1501 | — | Not comparable |
| AA ITBenchSource | 56.2% | — | Not comparable |
| AA Tau3 BankingSource | 33.0% | — | Not comparable |
| AA AutomationBenchSource | 51.2% | — | Not comparable |
| AA Harvey LABSource | 87.2% | — | Not comparable |
| terminalBenchHardSource | 65.9% | — | Not comparable |
| aaTerminalBench21Source | 88% | — | Not comparable |
| APEX-Agents-AASource | — | 11.5% | Not comparable |
| Gert LabsSource | — | 32.58% | Not comparable |
CodingKimi K2.5 (Reasoning) wins10 benchmarks
| Benchmark | GPT-5.6 Sol | Kimi K2.5 (Reasoning) | Result |
|---|---|---|---|
| SWE-bench ProSource | 64.6% | — | Not comparable |
| Terminal-Bench 2.0Source | 91.9% | — | Not comparable |
| deepSweSource | 72.7% | — | Not comparable |
| FrontierCode 1.1 ExtendedSource | 60.6% | — | Not comparable |
| cursorBench32Source | 67.2% | — | Not comparable |
| VulcanBench v3Source | 87.0% | — | Not comparable |
| AA Coding IndexSource | 77.4% | 46.8% | GPT-5.6 Sol leads |
| AA-SciCodeSource | 56.1% | 49.0% | GPT-5.6 Sol leads |
| SWE-bench VerifiedSource | — | 76.8% | Not comparable |
| Vibe Code BenchSource | — | 17.54% | Not comparable |
Reasoning4 benchmarks
KnowledgeGPT-5.6 Sol wins11 benchmarks
| Benchmark | GPT-5.6 Sol | Kimi K2.5 (Reasoning) | Result |
|---|---|---|---|
| GPQASource | 94.6% | 87.6% | GPT-5.6 Sol leads |
| GPQA-DSource | 94.6% | — | Not comparable |
| HealthBench ProfessionalSource | 60.5% | — | Not comparable |
| HealthBench HardSource | 33.1% | — | Not comparable |
| Artificial Analysis Intelligence IndexSource | 58.9% | 35.4% | GPT-5.6 Sol leads |
| AA-GPQA DiamondSource | 94.1% | 87.9% | GPT-5.6 Sol leads |
| AA-HLESource | 47.2% | 29.4% | GPT-5.6 Sol leads |
| AA-Omniscience IndexSource | 21.7% | -8.1% | GPT-5.6 Sol leads |
| AA-Omniscience AccuracySource | 58.5% | 34.3% | GPT-5.6 Sol leads |
| AA-Omniscience Hallucination RateSource | 88.8% | 64.6% | Kimi K2.5 (Reasoning) leads |
| MMLU-ProSource | — | 87.1% | Not comparable |
Math4 benchmarks
MultimodalGPT-5.6 Sol wins4 benchmarks
Inst. Following1 benchmarks
| Benchmark | GPT-5.6 Sol | Kimi K2.5 (Reasoning) | Result |
|---|---|---|---|
| AA-IFBenchSource | 72.7% | 70.2% | GPT-5.6 Sol leads |
Frequently Asked Questions (5)
Which is better, GPT-5.6 Sol or Kimi K2.5 (Reasoning)?
GPT-5.6 Sol is ahead on BenchLM's BenchAlign leaderboard, 81.96 to 59.35. The biggest single separator in this matchup is Terminal-Bench 2.0, where the scores are 91.9% and 50.8%.
Which is better for knowledge tasks, GPT-5.6 Sol or Kimi K2.5 (Reasoning)?
GPT-5.6 Sol has the edge for knowledge tasks in this comparison, averaging 94.6 versus 87.2. Inside this category, AA-Omniscience Index is the benchmark that creates the most daylight between them.
Which is better for coding, GPT-5.6 Sol or Kimi K2.5 (Reasoning)?
Kimi K2.5 (Reasoning) has the edge for coding in this comparison, averaging 76.8 versus 64.6. Inside this category, AA Coding Index is the benchmark that creates the most daylight between them.
Which is better for agentic tasks, GPT-5.6 Sol or Kimi K2.5 (Reasoning)?
GPT-5.6 Sol has the edge for agentic tasks in this comparison, averaging 92 versus 55. Inside this category, GDPval-AA is the benchmark that creates the most daylight between them.
Which is better for multimodal and grounded tasks, GPT-5.6 Sol or Kimi K2.5 (Reasoning)?
GPT-5.6 Sol has the edge for multimodal and grounded tasks in this comparison, averaging 83 versus 78.5. Inside this category, AA-MMMU-Pro is the benchmark that creates the most daylight between them.
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