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Grok 4 Fast (Reasoning)

Released 19 Sep 20252M contextproprietaryAlso written as grok/grok-4-fast-reasoning

2 results on 2 of 13 boards, latest measured Sep 2026. Compare with other models

Clinical Benchmarks Index27.1Rank 74 of 1492 of 10 boardsAverage × multiplier 46.9 × 0.577 = 27.1This site’s own calculation. Working How it is computed

Results

Each line sits on its own board's scale. Tall tick: the board leader.

Documentation and coding

  1. MedScribe (Vals AI)
    model ID grok/grok-4-fast-reasoning; temperature=1; top_p=0.95; max_output_tokens=30000
    81.63
    Rank 50 of 105Leader Claude Opus 5.5 91.43
    Official leaderboard
    Measured Sep 2026
  2. MedCode (Vals AI)
    model ID grok/grok-4-fast-reasoning; temperature=1; top_p=0.95; max_output_tokens=30000
    37.38
    Rank 72 of 103Leader Claude Opus 5 63.57
    Official leaderboard
    Measured Sep 2026

Index working

The Clinical Benchmarks Index is this site's own calculation: a weighted average of the board scores times a multiplier for the boards behind it. How it is computed

  • MedScribe (Vals AI)81.6381.6×0.25, near its ceilingNear its ceiling: leader 91.4, weight 0.25model ID grok/grok-4-fast-reasoning; temperature=1; top_p=0.95; max_output_tokens=30000
  • MedCode (Vals AI)37.3837.4×0.911model ID grok/grok-4-fast-reasoning; temperature=1; top_p=0.95; max_output_tokens=30000
Weighted average of 2 boards
46.9
Multiplier for 2 of 10 boards
× 0.577
Index
46.9 × 0.577 = 27.1

Score: the result on the board’s own 0 to 100 scale. Dot: this model; tick: the board’s leader. Weight: how much the board counts in the weighted average; bold where the board is near its ceiling and counts for less. Each result links to its quote and page; the line under it is the setting it was measured with.

Sources

The quote, page and document for each of the 2 results
  1. 50MedScribe (Vals AI) grok-4-fast-reasoning 81.63
    Printed as 81.63%Official leaderboard, measured Sep 2026Configuration: model ID grok/grok-4-fast-reasoning; temperature=1; top_p=0.95; max_output_tokens=30000
    Vals AI MedScribe leaderboard official leaderboard, Vals AI, 3 Sep 2026. Vals AI MedScribe leaderboard, View: All Models, Task: Overall, row 50 of 105 (Grok 4 Fast (Reasoning)), Accuracy column; Updated 9/29/2026. Rendered BenchmarkView table; configuration from embedded astro-island BenchmarkView props, benchmarkView.default.tasks.overall["grok/grok-4-fast-reasoning"].
    50 | Grok 4 Fast (Reasoning) | 81.63%±2.14 | $0.2/$0.5 | 12.42s
    Every result from this document
  2. 72MedCode (Vals AI) grok-4-fast-reasoning 37.38
    Printed as 37.38%Official leaderboard, measured Sep 2026Configuration: model ID grok/grok-4-fast-reasoning; temperature=1; top_p=0.95; max_output_tokens=30000
    Vals AI MedCode leaderboard official leaderboard, Vals AI, 29 Sep 2026. MedCode leaderboard, Overall task, All Models expanded, rank 72 of 103; Accuracy column; board Updated 9/29/2026. Rendered table row; configuration from embedded BenchmarkView props benchmarkView.default.tasks.overall["grok/grok-4-fast-reasoning"].
    72 | Grok 4 Fast (Reasoning) | 37.38%±1.94 | $0.2/$0.5 | 17.52s
    Every result from this document

Other SpaceX AI models: Grok 4, Grok 4.1 Fast Non-Reasoning, Grok 4.1 Fast (Reasoning), Grok 4.20, Grok 4.3, Grok 4.5, Grok 4.6, Grok 4.7, Grok 4 Fast (Non-Reasoning)