Grok 4.1 Fast (Reasoning) is the reasoning-enabled configuration of Grok 4.1 Fast, with extended thinking always active. The model produces explicit chain-of-thought traces before its final answer, delivering higher accuracy on complex analytical tasks at the cost of additional latency. It shares the same 2M-token context window and tool-calling capabilities as the standard variant, making it suited for tasks where correctness on difficult problems justifies the extra thinking time.
Grok SuperGrokGrok SuperGrok HeavyAPI|VisionReasoningWeb Search|Proprietary Model
Knowledge Cutoff
2025-06-01
Input → Output Format
Context Memory
2MIN33KOUT
AI Performance Evaluation
Arena Overall Score
1432
±4As of 2026-04-23
Overall Rank
No.57
46,539 Votes
Arena by Ability
Hard Prompts
1442±5No.69
Expert Knowledge
1438±11No.74
Instruction Following
1401±6No.86
Conversation Memory
1416±7No.79
Creative
1412±8No.45
Coding
1464±6No.72
Math
1421±11No.67
Arena by Occupation
Creative Writing
1405±6No.65
Social Sciences
1450±7No.55
Media
1400±7No.54
Business
1417±7No.68
Healthcare
1447±11No.66
Legal
1426±11No.73
Software
1460±5No.62
Mathematics
1422±13No.71
Source:Arena Intelligence
Overall
AA Intelligence Index
39%↑0%
LiveBench
60%↑0%
ForecastBench
60%↑1%
Reasoning & Math
AA Math Index
89%↑16%
GPQA Diamond
85%↑4%
HLE
18%↑0%
MMLU-Pro
85%↑3%
AIME 2025
89%↑16%
LB Reasoning
80%↑21%
LB Math
84%↑10%
LB Data
52%↑3%
Coding
AA Coding Index
31%↓3%
LiveCodeBench
82%↑17%
LB Coding
70%↓4%
LB Agentic
32%↓12%
TAU2
93%↑20%
TerminalBench
24%↓7%
SciCode
44%↑3%
Language & Instructions
IFBench
53%↓4%
AA-LCR
68%↑6%
Hallucination (HHEM)
19%↑9%
Factual (HHEM)
81%↓9%
LB Language
74%↑3%
LB IF
28%↓18%
Output Speed
Standard Mode
114tok/s↑32
First Output 0.30s
Reasoning Mode
141tok/s↑53
First Output 11.23s
