Compare AI models
| Specifications | ||
Context windowHow much information the model can work with in one request, measured in tokens — pieces of words or other data. This includes your question, attachments, conversation and reply. Limits can vary by model variant and provider. | 400k | 2M |
| These models have no shared benchmark scores. | ||
BullshitBench v2Nonsense detection — Given 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% | — |
| Overview | ||
| Company | OpenAI | SpaceXSI |
| Release date | Sep 15 2025 | Sep 19 2025 |
| Access | Closed | Closed |
| Model details | View model | View model |
Other comparisons
GPT-5-CodexvsClaude Haiku 5.5Grok 4 FastvsClaude Haiku 5.5GPT-5-CodexvsGemini 4 ArgonGrok 4 FastvsGemini 4 ArgonGPT-5-CodexvsMuse Spark OpenGrok 4 FastvsMuse Spark OpenGPT-5-CodexvsDeepSeek-V4.1-Flash-1017Grok 4 FastvsDeepSeek-V4.1-Flash-1017GPT-5-CodexvsMistral Large 4Grok 4 FastvsMistral Large 4GPT-5-CodexvsKimi K3Grok 4 FastvsKimi K3Frequently asked questions
GPT-5-Codex and Grok 4 Fast don't publish scores on any of the same benchmarks, so there's no direct head-to-head comparison. GPT-5-Codex shipped 4 days before Grok 4 Fast, so benchmark comparisons should account for the intervening progress.
Context windows are 400k (GPT-5-Codex) vs 2M (Grok 4 Fast).
Direct benchmark comparisons are unavailable — GPT-5-Codex and Grok 4 Fast don't publish scores on any of the same benchmarks.