GPT-5 Codex vs GPT-1
Compare GPT-5 Codex and GPT-1, both from OpenAI, tested across 7 shared challenges. Updated April 2026.
Which is better, GPT-5 Codex or GPT-1?
GPT-5 Codex and GPT-1 are both competitive models. Compare their real outputs side by side below.
Key Differences Between GPT-5 Codex and GPT-1
GPT-5 Codex is made by openai while GPT-1 is from openai.
Our Verdict
GPT-5 Codex
GPT-1Runner-up
No community votes yet. On paper, GPT-5 Codex has the edge — bigger model tier, newer.
Too close to call
Writing DNA
Style Comparison
Similarity
72%
GPT-5 Codex uses 229.7x more bold
GPT-5 Codex
GPT-1
64%Vocabulary65%
17wSentence Length14w
0.38Hedging0.27
2.3Bold0.0
3.5Lists0.3
0.15Emoji0.00
0.49Headings0.00
0.05Transitions0.41
Based on 13 + 7 text responses
vsAsk them anything yourself
Some models write identically. You are paying for the brand.
178 models fingerprinted across 32 writing dimensions. Free research.
Model Similarity Index
185x
price gap between models that write identically
178
models
12
clone pairs
32
dimensions
Devstral M / S
95.7%
Qwen3 Coder / Flash
95.6%
GPT-5.4 / Mini
93.3%
279 AI models invented the same fake scientist.
We read every word. 250 models. 2.14 million words. This is what we found.
Free preview13 of 58 slides
FAQ
