Grok 3 Thinking vs xAI: Grok 4 Fast (free)
Compare Grok 3 Thinking and xAI: Grok 4 Fast (free), both from xAI, context windows of 128K vs 2.0M, tested across 14 shared challenges.
Our Verdict
Grok 3 Thinking
xAI: Grok 4 Fast (free)
No community votes yet. On paper, these are closely matched - try both with your actual task to see which fits your workflow.
Too close to call
API pricing
Cost per 1M tokens
Grok 3 Thinking
Input
—
Output
—
xAI: Grok 4 Fast (free)
Input
$0.000
Output
$0.000
Writing DNA
Style Comparison
Similarity
52%
xAI: Grok 4 Fast (free) uses 2.5x more headings
Grok 3 Thinking
xAI: Grok 4 Fast (free)
46%Vocabulary65%
19wSentence Length13w
1.11Hedging0.56
3.3Bold1.4
2.6Lists2.5
0.00Emoji0.00
0.64Headings1.58
0.25Transitions0.28
Based on 6 + 14 text responses
Research
What we learned reading every model
FAQ
