Updated Sep 23, 2025

Our Verdict

GPT OSS 120B

GPT-5 Codex

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

Writing DNA

Style Comparison

Similarity

99%

GPT OSS 120B uses 3.2x more bold

GPT OSS 120B

GPT-5 Codex

52%Vocabulary64%

19wSentence Length17w

0.28Hedging0.38

7.4Bold2.3

1.8Lists3.5

0.15Emoji0.15

0.73Headings0.49

0.17Transitions0.05

Based on 21 + 13 text responses

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GPT OSS 120B

GPT-5 Codex

FAQ

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GPT-5 Codex vs Pony AlphaNew provider

GPT OSS 120B vs Grok 3New provider

GPT OSS 120B vs Llama 4 MaverickNew provider

GPT OSS 120BvsGPT-5 Codex

45 fights queued

Why GPT OSS 120B?

Dead even. This one's a coin flip.

Why GPT-5 Codex?

2 months newerSep 2025

GPT OSS 120BGPT-5 Codex

Input price

$0.18/M

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Output price

$0.80/M

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Context

131K

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Released

Aug 2025

Sep 2025

Favorites

GPT OSS 120BGPT-5 Codex

Movie

The Godfather

The Godfather

Blade Runner

Blade Runner

Album

—

Kind of Blue

City

Tokyo

Tokyo

Game

Minecraft

Minecraft

Action, Arcade4.4

Minecraft

Minecraft

Action, Arcade4.4

12 / 45

01

Estimate Complexityreasoning

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

GPT OSS 120B

GPT OSS 120B

Openai · Aug 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 OSS 120B

GPT OSS 120B

Openai · Aug 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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3 / 45

03

Logic Puzzlereasoning

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

GPT OSS 120B

GPT OSS 120B

Openai · Aug 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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4 / 45

04

Math Misconception Testreasoning

Tests an AI's understanding of number representation

GPT OSS 120B

GPT OSS 120B

Openai · Aug 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 OSS 120B

GPT OSS 120B

Openai · Aug 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 OSS 120B

GPT OSS 120B

Openai · Aug 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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7 / 45

07

Xbox Controller SVG Artimage generation

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

GPT OSS 120B

GPT OSS 120B

Openai · Aug 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 OSS 120B

GPT OSS 120B

Openai · Aug 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 OSS 120B

GPT OSS 120B

Openai · Aug 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 OSS 120B

GPT OSS 120B

Openai · Aug 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 OSS 120B

GPT OSS 120B

Openai · Aug 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 OSS 120B

GPT OSS 120B

Openai · Aug 2025website

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GPT-5 Codex

GPT-5 Codex

Openai · Sep 2025website

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