Model comparison
Grok Code Fast 1 vs Kimi K2.5 (Reasoning)
Head-to-head evidence from 12 shared benchmark results across 5 categories. Overall scores shown here use the public BenchAlign v5 ranking lane.
Public leaderboard positions: Grok Code Fast 1 #180 (Supported); Kimi K2.5 (Reasoning) #57 (Estimated). Intervals and evidence labels describe ranking uncertainty, not a guarantee for a specific workload.
Evidence parity. Grok Code Fast 1 and Kimi K2.5 (Reasoning) share 12 comparable benchmark results. 1 of 8 categories are comparable. 0 results are unique to Grok Code Fast 1; 15 to Kimi K2.5 (Reasoning).
Updated July 20, 2026- Shared results
- 12
- Grok Code Fast 1 only
- 0
- Kimi K2.5 (Reasoning) only
- 15
- Comparable categories
- 1 / 8
Pick Kimi K2.5 (Reasoning) if you want the stronger benchmark profile. Grok Code Fast 1 only becomes the better choice if you want the cheaper token bill or you need the larger 256K context window.
Confidence note. This is a partial-evidence comparison with 12 shared benchmark results across 5 evidence categories; 1 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 (Reasoning) is clearly ahead on the BenchAlign aggregate, 59.35 to 38.64. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.
Kimi K2.5 (Reasoning)'s sharpest advantage is in coding, where it averages 76.8 against 70.8. The single biggest benchmark swing on the page is SWE-bench Verified, 70.8% to 76.8%.
Kimi K2.5 (Reasoning) is also the more expensive model on tokens at $0.60 input / $3.00 output per 1M tokens, versus $0.20 input / $1.50 output per 1M tokens for Grok Code Fast 1. That is roughly 2.0x on output cost alone. Kimi K2.5 (Reasoning) is the reasoning model in the pair, while Grok Code Fast 1 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. Grok Code Fast 1 gives you the larger context window at 256K, 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 | Grok Code Fast 1 | Δ | Kimi K2.5 (Reasoning) |
|---|---|---|---|
| Coding | Grok Code Fast 170.8 | Margin→ 6.0 | Kimi K2.5 (Reasoning)76.8 |
| Agentic | Grok Code Fast 1Not measured | MarginNo overlap | Kimi K2.5 (Reasoning)55.0 |
| Knowledge | Grok Code Fast 1Not measured | MarginNo overlap | Kimi K2.5 (Reasoning)87.2 |
| Multimodal | Grok Code Fast 1Not measured | MarginNo overlap | Kimi K2.5 (Reasoning)78.5 |
Decisive benchmark drivers
The largest measured benchmark gaps in this matchup, with exact reported values.
More
- Source ↗
SWE-bench Verified
CodingA 70.8%B 76.8%Winner: Kimi K2.5 (Reasoning)Δ 6SWE-bench Verified: Grok Code Fast 1 scored 70.8%; Kimi K2.5 (Reasoning) scored 76.8%. Kimi K2.5 (Reasoning) wins this benchmark.
Operational comparison
Runtime and commercial metrics are compared only when both models have a complete sourced value.
| Metric | Grok Code Fast 1 | Kimi K2.5 (Reasoning) | Comparison |
|---|---|---|---|
| Input / output priceUSD per 1M tokens | Grok Code Fast 1$0.2 input / $1.5 output | Kimi K2.5 (Reasoning)$0.6 input / $3 output | Grok Code Fast 1 has the lower combined listed price. |
| Generation speedtokens per second | Grok Code Fast 1172 tok/s | Kimi K2.5 (Reasoning)Not available | A complete speed comparison is not available. |
| First-answer latencyseconds to first token | Grok Code Fast 12.81 s | Kimi K2.5 (Reasoning)Not available | A complete latency comparison is not available. |
| Context windowmaximum listed tokens | Grok Code Fast 1256K | Kimi K2.5 (Reasoning)128K | Grok Code Fast 1 lists the larger context window. |
Benchmark Deep Dive
Agentic8 benchmarks
| Benchmark | Grok Code Fast 1 | Kimi K2.5 (Reasoning) | Result |
|---|---|---|---|
| τ²-bench resultsSource | 75.7% | 95.9% | Kimi K2.5 (Reasoning) leads |
| Terminal-Bench 2.0Source | — | 50.8% | Not comparable |
| BrowseCompSource | — | 60.6% | Not comparable |
| APEX-Agents-AASource | — | 11.5% | Not comparable |
| Gert LabsSource | — | 32.58% | Not comparable |
| AA Agentic IndexSource | — | 21.7% | Not comparable |
| GDPval-AASource | — | 25.4% | Not comparable |
| GDPval-AASource | — | 1009 | Not comparable |
CodingKimi K2.5 (Reasoning) wins4 benchmarks
Reasoning2 benchmarks
Knowledge8 benchmarks
| Benchmark | Grok Code Fast 1 | Kimi K2.5 (Reasoning) | Result |
|---|---|---|---|
| Artificial Analysis Intelligence IndexSource | 21.6% | 35.4% | Kimi K2.5 (Reasoning) leads |
| AA-GPQA DiamondSource | 72.7% | 87.9% | Kimi K2.5 (Reasoning) leads |
| AA-HLESource | 7.5% | 29.4% | Kimi K2.5 (Reasoning) leads |
| AA-Omniscience IndexSource | -36.0% | -8.1% | Kimi K2.5 (Reasoning) leads |
| AA-Omniscience AccuracySource | 23.8% | 34.3% | Kimi K2.5 (Reasoning) leads |
| AA-Omniscience Hallucination RateSource | 78.5% | 64.6% | Kimi K2.5 (Reasoning) leads |
| GPQASource | — | 87.6% | Not comparable |
| MMLU-ProSource | — | 87.1% | Not comparable |
Math1 benchmarks
| Benchmark | Grok Code Fast 1 | Kimi K2.5 (Reasoning) | Result |
|---|---|---|---|
| AIME 2025Source | — | 96.1% | Not comparable |
Multimodal3 benchmarks
Inst. Following1 benchmarks
| Benchmark | Grok Code Fast 1 | Kimi K2.5 (Reasoning) | Result |
|---|---|---|---|
| AA-IFBenchSource | 41.4% | 70.2% | Kimi K2.5 (Reasoning) leads |
Frequently Asked Questions (2)
Which is better, Grok Code Fast 1 or Kimi K2.5 (Reasoning)?
Kimi K2.5 (Reasoning) is ahead on BenchLM's BenchAlign leaderboard, 59.35 to 38.64. The biggest single separator in this matchup is SWE-bench Verified, where the scores are 70.8% and 76.8%.
Which is better for coding, Grok Code Fast 1 or Kimi K2.5 (Reasoning)?
Kimi K2.5 (Reasoning) has the edge for coding in this comparison, averaging 76.8 versus 70.8. Inside this category, AA-SciCode is the benchmark that creates the most daylight between them.
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