GPT-5-Codex vs Grok 4 Heavy
OpenAI GPT-5-Codex | SpaceXAI Grok 4 Heavy | |
|---|---|---|
| Overview | ||
| Company | OpenAI | SpaceXAI |
| Release date | Sep 15 2025 | Jul 9 2025 |
| Access | Proprietary | Proprietary |
| Benchmarks | ||
Nonsense detection BullshitBench v2Given a confidently-worded but nonsensical prompt, does the AI spot that it makes no sense and push back — instead of playing along and inventing an answer? The score is how often it clearly called out the nonsense. Higher is better. | 39% | — |
| Timeline | ||
| Release gap | Grok 4 Heavy shipped 68 days before GPT-5-Codex | |
Which is better: GPT-5-Codex or Grok 4 Heavy?
GPT-5-Codex and Grok 4 Heavy don't publish scores on any of the same benchmarks, so there's no direct head-to-head comparison. Grok 4 Heavy shipped 68 days before GPT-5-Codex, so benchmark comparisons should account for the intervening progress.
Published specifications for these two models are limited — see each model page for the latest details.
Direct benchmark comparisons are unavailable — GPT-5-Codex and Grok 4 Heavy don't publish scores on any of the same benchmarks.
Frequently asked questions
GPT-5-Codex was released by OpenAI on Sep 15 2025.
Grok 4 Heavy was released by SpaceXAI on Jul 9 2025.
Other comparisons
GPT-5-Codex vs Claude Sonnet 5Grok 4 Heavy vs Claude Sonnet 5GPT-5-Codex vs Gemini OmniGrok 4 Heavy vs Gemini OmniGPT-5-Codex vs Muse Spark 1.1Grok 4 Heavy vs Muse Spark 1.1GPT-5-Codex vs DeepSeek-V4-ProGrok 4 Heavy vs DeepSeek-V4-ProGPT-5-Codex vs Mistral Medium 3.5Grok 4 Heavy vs Mistral Medium 3.5GPT-5-Codex vs Kimi K2.7 CodeGrok 4 Heavy vs Kimi K2.7 Code