Model comparison
Composer 2 Fast vs Kimi K2.5 (Reasoning)
Head-to-head evidence from 0 shared benchmark results across 0 categories. Overall scores shown here use the public BenchAlign v5 ranking lane.
Public leaderboard positions: Composer 2 Fast unranked (Not scored); Kimi K2.5 (Reasoning) #64 (Estimated). Intervals and evidence labels describe ranking uncertainty, not a guarantee for a specific workload.
Evidence parity. Composer 2 Fast and Kimi K2.5 (Reasoning) share 0 comparable benchmark results. 0 of 8 categories are comparable. 1 result is unique to Composer 2 Fast; 27 to Kimi K2.5 (Reasoning).
Updated July 28, 2026- Shared results
- 0
- Composer 2 Fast only
- 1
- Kimi K2.5 (Reasoning) only
- 27
- Comparable categories
- 0 / 8
Benchmark data for Composer 2 Fast and Kimi K2.5 (Reasoning) is coming soon on BenchLM.
Confidence note. This is a partial-evidence comparison with 0 shared benchmark results across 0 evidence categories; 0 of 8 categories currently have scoreable aggregates for both models. Treat the verdict as directional until coverage is more balanced.
Why this result
BenchLM has partial data for these models, but not enough overlapping benchmark coverage to produce a fair score-level comparison yet.
Composer 2 Fast has the larger context window at 200K, compared with 128K for Kimi K2.5 (Reasoning).
Operational comparison
Runtime and commercial metrics are compared only when both models have a complete sourced value.
| Metric | Composer 2 Fast | Kimi K2.5 (Reasoning) | Comparison |
|---|---|---|---|
| Input / output priceUSD per 1M tokens | Composer 2 FastNot available | Kimi K2.5 (Reasoning)$0.6 input / $3 output | A complete price comparison is not available. |
| Generation speedtokens per second | Composer 2 FastNot available | Kimi K2.5 (Reasoning)Not available | A complete speed comparison is not available. |
| First-answer latencyseconds to first token | Composer 2 FastNot available | Kimi K2.5 (Reasoning)Not available | A complete latency comparison is not available. |
| Context windowmaximum listed tokens | Composer 2 Fast200K | Kimi K2.5 (Reasoning)128K | Composer 2 Fast lists the larger context window. |
Benchmark Deep Dive
Agentic8 benchmarks
| Benchmark | Composer 2 Fast | Kimi K2.5 (Reasoning) | Result |
|---|---|---|---|
| Terminal-Bench 2.0Source | — | 50.8% | Not comparable |
| BrowseCompSource | — | 60.6% | Not comparable |
| APEX-Agents-AASource | — | 11.5% | Not comparable |
| τ²-bench resultsSource | — | 95.9% | Not comparable |
| Gert LabsSource | — | 32.58% | Not comparable |
| AA Agentic IndexSource | — | 21.7% | Not comparable |
| GDPval-AASource | — | 25.1% | Not comparable |
| GDPval-AASource | — | 1003 | Not comparable |
Coding5 benchmarks
Reasoning2 benchmarks
Knowledge8 benchmarks
| Benchmark | Composer 2 Fast | Kimi K2.5 (Reasoning) | Result |
|---|---|---|---|
| GPQASource | — | 87.6% | Not comparable |
| MMLU-ProSource | — | 87.1% | 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 |
Math1 benchmarks
| Benchmark | Composer 2 Fast | Kimi K2.5 (Reasoning) | Result |
|---|---|---|---|
| AIME 2025Source | — | 96.1% | Not comparable |
Multimodal3 benchmarks
Inst. Following1 benchmarks
| Benchmark | Composer 2 Fast | Kimi K2.5 (Reasoning) | Result |
|---|---|---|---|
| AA-IFBenchSource | — | 70.2% | Not comparable |
Frequently Asked Questions (3)
Can I compare Composer 2 Fast and Kimi K2.5 (Reasoning) on BenchLM yet?
Not fully yet. BenchLM is tracking both models, but the sourced benchmark breakdown for this comparison is still coming soon.
Why does this comparison show “coming soon”?
BenchLM only shows category winners and benchmark-level calls when we have sourced results that can be compared fairly. For these models, the public benchmark coverage is not complete enough yet.
What data is available for Composer 2 Fast and Kimi K2.5 (Reasoning) today?
Kimi K2.5 (Reasoning): $0.60 input / $3.00 output per 1M tokens Both model pages still include creator, context window, reasoning mode, and other metadata while benchmark coverage fills in.
Related Comparisons
Explore More
Know when it’s worth switching models
The model to choose, the cheaper alternative, and the release we would wait on.
One email each week. Unsubscribe anytime.