GPT-4 vs xAI: Grok 4 Fast (free)
Compare GPT-4 by OpenAI against xAI: Grok 4 Fast (free) by xAI, context windows of 8K vs 2.0M, tested across 10 shared challenges. Updated April 2026.
Which is better, GPT-4 or xAI: Grok 4 Fast (free)?
GPT-4 and xAI: Grok 4 Fast (free) are both competitive models. GPT-4 costs $30/M input tokens vs $0/M for xAI: Grok 4 Fast (free). Context windows: 8K vs 2000K tokens. Compare their real outputs side by side below.
Key Differences Between GPT-4 and xAI: Grok 4 Fast (free)
GPT-4 is made by openai while xAI: Grok 4 Fast (free) is from xai. GPT-4 has a 8K token context window compared to xAI: Grok 4 Fast (free)'s 2000K. On pricing, GPT-4 costs $30/M input tokens vs $0/M for 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.
Style Comparison
xAI: Grok 4 Fast (free) uses 157.7x more headings
vs
Ask them anything yourself
Some models write identically. You are paying for the brand.
178 models fingerprinted across 32 writing dimensions. Free research.
185x
price gap between models that write identically
178
models
12
clone pairs
32
dimensions
279 AI models invented the same fake scientist.
We read every word. 250 models. 2.14 million words. This is what we found.
