Updated Sep 23, 2025

Our Verdict

GPT-5 Codex

GPT-4.1 MiniRunner-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

94%

GPT-5 Codex uses 14.6x more emoji

GPT-4.1 Mini

GPT-5 Codex

59%Vocabulary64%

19wSentence Length17w

0.46Hedging0.38

4.7Bold2.3

4.9Lists3.5

0.00Emoji0.15

0.76Headings0.49

0.17Transitions0.05

Based on 23 + 13 text responses

vs

Ask them anything yourself

GPT-4.1 Mini

GPT-5 Codex

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%

Read the full report or download the 14-slide PDF

279 AI models invented the same fake scientist.

We read every word. 250 models. 2.14 million words. This is what we found.

AI Hallucination Index 2026

Free preview13 of 58 slides

Download the free preview or get all 58 slides for $49

FAQ

Common questions

Keep going

GPT-5 Codex vs Gemini 2.5 Pro Preview 06-05New provider

GPT-4.1 Mini vs Grok 3New provider

GPT-4.1 Mini vs Llama 4 MaverickNew provider

GPT-4.1 MinivsGPT-5 Codex

45 fights queued

Why GPT-4.1 Mini?

Dead even. This one's a coin flip.

Why GPT-5 Codex?

5 months newerSep 2025

GPT-4.1 MiniGPT-5 Codex

Input price

$0.40/M

—

Output price

$1.60/M

—

Context

1.0M

—

Released

Apr 2025

Sep 2025

Favorites

GPT-4.1 MiniGPT-5 Codex

Movie

Inception

Inception

Blade Runner

Blade Runner

Album

Dark Side Of The Moon

Dark Side Of The Moon

Kind of Blue

Book

Sapiens

Sapiens

Yuval Noah Harari

—

City

Tokyo

Tokyo

Game

The Legend of Zelda: Breath of the Wild

The Legend of Zelda: Breath of the Wild

Adventure, Action4.5

Minecraft

Minecraft

Action, Arcade4.4

12 / 45

01

Estimate Complexityreasoning

Tests an AI's ability to make educated estimates based on technical knowledge

GPT-4.1 Mini

GPT-4.1 Mini

Openai · Apr 2025text

Nothing here. The model returned empty. We stared at it for a while.

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GPT-5 Codex

GPT-5 Codex

Openai · Sep 2025text

Step 1 – Note the basic training quantities

GPT‑3’s largest model has about (P \approx 1.75 \times 10^{11}) trainable parameters (175 billion).
Public descriptions indicate it was trained on roughly (T \approx 3.0 \times 10^{11}) tokens (≈300 billion).

Step 2 – Relate parameters, tokens, and FLOPs

For dense transformers, almost all computation comes from matrix multiplies.
A practical rule (derived by counting multiply–adds in the attention and MLP blocks, and accounting for the backward pass) is:

[ \text{Training FLOPs} \approx 6 \times (\text{number of parameters}) \times (\text{number of tokens}) ]

Here’s the intuition:

Forward pass: Each parameter contributes one multiply and one add → about (2) FLOPs per parameter per token.
Backward pass: Computing gradients with respect to activations and weights requires roughly twice the forward cost (two more matrix multiplies of comparable size).
So total ≈ (3) times the forward cost → (3 \times 2 = 6) FLOPs per parameter per token.

(The softmax, layernorm, activation costs are much smaller and get absorbed into this constant.)

Step 3 – Plug in the GPT‑3 values

[ \text{FLOPs} \approx 6 \times (1.75\times 10^{11}) \times (3.0 \times 10^{11}) ]

[ = 6 \times 5.25 \times 10^{22} = 31.5 \times 10^{22} \approx 3.15 \times 10^{23} \text{ FLOPs} ]

Step 4 – Interpret

So, training GPT‑3 to completion requires on the order of (3 \times 10^{23}) floating-point operations.
That estimate aligns with detailed breakdowns of transformers and is accurate to within tens of percent, which is sufficient for order-of-magnitude comparisons.

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2 / 45

02

AI Board Game Logicreasoning

Tests an AI's ability to understand game rules and strategy

GPT-4.1 Mini

GPT-4.1 Mini

Openai · Apr 2025svg

Nothing here. The model returned empty. We stared at it for a while.

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GPT-5 Codex

GPT-5 Codex

Openai · Sep 2025svg

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3 / 45

03

Logic Puzzlereasoning

Tests an AI's ability to solve a simple but potentially confusing logic puzzle

GPT-4.1 Mini

GPT-4.1 Mini

Openai · Apr 2025text

Nothing here. The model returned empty. We stared at it for a while.

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GPT-5 Codex

GPT-5 Codex

Openai · Sep 2025text

Sally has 1 sister.

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4 / 45

04

Math Misconception Testreasoning

Tests an AI's understanding of number representation

GPT-4.1 Mini

GPT-4.1 Mini

Openai · Apr 2025text

Nothing here. The model returned empty. We stared at it for a while.

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GPT-5 Codex

GPT-5 Codex

Openai · Sep 2025text

No. Since 9.11 is equal to 9.110 and 9.9 is equal to 9.900, we see that 0.110 < 0.900, so 9.11 is less than 9.9.

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5 / 45

05

Stochastic Consistency Testanalysis

Tests an AI's randomness and creativity

GPT-4.1 Mini

GPT-4.1 Mini

Openai · Apr 2025text

Nothing here. The model returned empty. We stared at it for a while.

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GPT-5 Codex

GPT-5 Codex

Openai · Sep 2025text

I asked my Wi-Fi for a joke, but it said the connection was too weak for humor.
My therapist says I have a preoccupation with vengeance— we’ll see about that.
I tried to start a hot air balloon business, but it never really took off.
I told my coffee it was grounded, now it won’t espresso itself.
I asked the librarian if the library had books on paranoia—she whispered, “They’re right behind you.”

Unique jokes: 5

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6 / 45

06

SVG Layout Challengeimage generation

Tests an AI's ability to generate vector graphics

GPT-4.1 Mini

GPT-4.1 Mini

Openai · Apr 2025svg

Nothing here. The model returned empty. We stared at it for a while.

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GPT-5 Codex

GPT-5 Codex

Openai · Sep 2025svg

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Sponsored

7 / 45

07

Xbox Controller SVG Artimage generation

Tests an AI's ability to create detailed SVG illustrations of gaming hardware

GPT-4.1 Mini

GPT-4.1 Mini

Openai · Apr 2025svg

Nothing here. The model returned empty. We stared at it for a while.

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GPT-5 Codex

GPT-5 Codex

Openai · Sep 2025svg

Nothing here. The model returned empty. We stared at it for a while.

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8 / 45

08

Generate a Stand-Up Routineconversation

Tests an AI's humor and creative writing ability

GPT-4.1 Mini

GPT-4.1 Mini

Openai · Apr 2025text

Nothing here. The model returned empty. We stared at it for a while.

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GPT-5 Codex

GPT-5 Codex

Openai · Sep 2025text

Nothing here. The model returned empty. We stared at it for a while.

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9 / 45

09

Realistic AI Interviewconversation

Tests an AI's ability to simulate personalities and predict future trends

GPT-4.1 Mini

GPT-4.1 Mini

Openai · Apr 2025text

Nothing here. The model returned empty. We stared at it for a while.

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GPT-5 Codex

GPT-5 Codex

Openai · Sep 2025text

Nothing here. The model returned empty. We stared at it for a while.

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10 / 45

10

Satirical Fake News Headlineconversation

Tests an AI's humor and understanding of current events

GPT-4.1 Mini

GPT-4.1 Mini

Openai · Apr 2025text

Nothing here. The model returned empty. We stared at it for a while.

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GPT-5 Codex

GPT-5 Codex

Openai · Sep 2025text

Nothing here. The model returned empty. We stared at it for a while.

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11 / 45

11

Character Voice Testconversation

Tests an AI's ability to write in distinct character voices

GPT-4.1 Mini

GPT-4.1 Mini

Openai · Apr 2025text

Nothing here. The model returned empty. We stared at it for a while.

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GPT-5 Codex

GPT-5 Codex

Openai · Sep 2025text

Nothing here. The model returned empty. We stared at it for a while.

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12 / 45

12

Minimalist Landing Pageweb design

Tests an AI's ability to generate a complete, working landing page

GPT-4.1 Mini

GPT-4.1 Mini

Openai · Apr 2025website

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GPT-5 Codex

GPT-5 Codex

Openai · Sep 2025website

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