Model comparison
Grok 4 Fast (Reasoning) vs Leanstral
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: Grok 4 Fast (Reasoning) #76 (Supported); Leanstral unranked (Not scored). Intervals and evidence labels describe ranking uncertainty, not a guarantee for a specific workload.
Evidence parity. Grok 4 Fast (Reasoning) and Leanstral share 0 comparable benchmark results. 0 of 8 categories are comparable. 13 results are unique to Grok 4 Fast (Reasoning); 0 to Leanstral.
Updated July 23, 2026- Shared results
- 0
- Grok 4 Fast (Reasoning) only
- 13
- Leanstral only
- 0
- Comparable categories
- 0 / 8
Benchmark data for Grok 4 Fast (Reasoning) and Leanstral 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 does not have sourced benchmark coverage for Leanstral yet. This comparison is currently limited to metadata such as context window, reasoning mode, and pricing where available.
Grok 4 Fast (Reasoning) has the larger context window at 2M, compared with 256K for Leanstral.
Operational comparison
Runtime and commercial metrics are compared only when both models have a complete sourced value.
| Metric | Grok 4 Fast (Reasoning) | Leanstral | Comparison |
|---|---|---|---|
| Input / output priceUSD per 1M tokens | Grok 4 Fast (Reasoning)Not available | Leanstral$0 input / $0 output | A complete price comparison is not available. |
| Generation speedtokens per second | Grok 4 Fast (Reasoning)Not available | LeanstralNot available | A complete speed comparison is not available. |
| First-answer latencyseconds to first token | Grok 4 Fast (Reasoning)Not available | LeanstralNot available | A complete latency comparison is not available. |
| Context windowmaximum listed tokens | Grok 4 Fast (Reasoning)2M | Leanstral256K | Grok 4 Fast (Reasoning) lists the larger context window. |
Benchmark Deep Dive
Agentic1 benchmarks
| Benchmark | Grok 4 Fast (Reasoning) | Leanstral | Result |
|---|---|---|---|
| τ²-bench resultsSource | 65.8% | — | Not comparable |
Coding2 benchmarks
Reasoning2 benchmarks
Knowledge6 benchmarks
| Benchmark | Grok 4 Fast (Reasoning) | Leanstral | Result |
|---|---|---|---|
| Artificial Analysis Intelligence IndexSource | 27.4% | — | Not comparable |
| AA-GPQA DiamondSource | 84.7% | — | Not comparable |
| AA-HLESource | 17.0% | — | Not comparable |
| AA-Omniscience IndexSource | -28.4% | — | Not comparable |
| AA-Omniscience AccuracySource | 22.6% | — | Not comparable |
| AA-Omniscience Hallucination RateSource | 66.0% | — | Not comparable |
Multimodal1 benchmarks
| Benchmark | Grok 4 Fast (Reasoning) | Leanstral | Result |
|---|---|---|---|
| AA-MMMU-ProSource | 61.8% | — | Not comparable |
Inst. Following1 benchmarks
| Benchmark | Grok 4 Fast (Reasoning) | Leanstral | Result |
|---|---|---|---|
| AA-IFBenchSource | 50.5% | — | Not comparable |
Frequently Asked Questions (3)
Can I compare Grok 4 Fast (Reasoning) and Leanstral 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 Grok 4 Fast (Reasoning) and Leanstral today?
Leanstral: $0.00 input / $0.00 output per 1M tokens Both model pages still include creator, context window, reasoning mode, and other metadata while benchmark coverage fills in.
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