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Model

Grok 4.1 Fast NO.21

Cheap, fast, 2M-context workhorse for high throughput.

CompareBack to the index

xAI · Grok · Fast · Closed weights

Specification

Fig.01 — Grok — xAI

USA

Context window
2Mtokens
Max output
66Ktokens
Input price
$0.20/ 1M
Output price
$0.50/ 1M
Cached input
$0.05/ 1M
Throughput
250tok/s
Class
Fast
Modalities
Text, Image
Weights
Closed
Knowledge cutoff
May 2025
Released
Nov 2025

Overview

Grok 4.1 Fast is xAI's high-throughput, low-cost tier with a 2M-token context window and aggressive prompt-cache pricing. It is great value for search, summarization, and high-volume calls with real-time data access. It trades away reliability on complex reasoning and multi-step coding, so it is best as a fast utility model rather than an autonomous coding agent.

Strengths

  • Very low cost with cheap prompt caching
  • Huge 2M-token context window
  • Fast response latency
  • Real-time X/web data access

Trade-offs

  • Weaker on complex coding and agentic tasks
  • Lower reasoning depth than the flagship
  • Less consistent tool use
  • Shallower on hard STEM problems

Fit

Best for

  • High-volume, low-cost inference
  • Retrieval and summarization
  • Real-time search over large context
  • Simple classification and extraction

Not ideal for

  • Complex multi-file coding
  • Long-horizon agentic automation

Capabilities

Ten axes, normalized 0–100 and scored the same way across the whole catalog — so a 78 here means what a 78 means anywhere else on the bench.

Fig.02 — Capability radar

0 — 100

Reasoning
74
Coding
68
Math
80
Writing
76
Knowledge
80
Speed
92
Agentic
66
Vision
74
Multilingual
76
Long Context
85

Benchmarks

Public results, with independent third-party runs marked. Bars normalize percentages against 100 and Elo ratings against a 1500 ceiling.

Independent index

Artificial Analysis Intelligence Index

Composite of ~9–10 independent evals · Artificial Analysis

31/ 100

BenchmarkResult
Artificial Analysis Intelligence IndexIndependentGeneral · Artificial Analysis
31%
τ-benchIndependentAgentic · τ-bench
72.8%

Alternatives

Models in roughly the same class — the ones worth weighing against this record.

Compare side by side
01Grok 4.3xAIxAI's flagship: strong math reasoning and real-time knowledge at aggressive pricing.02MiniMax M3MiniMaxOpen-weight multimodal model with native video input and 1M context.03GPT-5.4 miniOpenAILow-cost previous-generation OpenAI workhorse for standard routing.

Index

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