GPT-5.1 vs Codex-Max Comparison Guide | Generated by AI
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Yes, GPT-5.1-Codex-Max is a real and impressive model!
GPT-5.1-Codex-Max was released by OpenAI in November 2025 as a specialized coding model. Here’s how it compares:
GPT-5.1-Codex-Max vs GPT-5.1
GPT-5.1-Codex-Max is specifically optimized for agentic coding tasks, while GPT-5.1 is a general-purpose model. Key differences:
Strengths of Codex-Max:
- Long-horizon coding: Uses “compaction” to work across millions of tokens and multiple context windows, enabling it to work on tasks for 24+ hours continuously
- 30% more token-efficient than GPT-5.1-Codex at the same reasoning level
- Better benchmark scores on coding tasks like SWE-bench Verified (77.9% vs 73.7%)
- Trained specifically on real-world software engineering workflows (PR creation, code review, debugging)
- Designed for complex refactors, multi-hour agent loops, and project-scale work
When to use each:
- Codex-Max: Use only for agentic coding tasks in Codex CLI or similar environments
- GPT-5.1: Better for general conversations, reasoning, and non-coding tasks
About GPT-4.1
There is no official model called GPT-4.1 from OpenAI. You might be thinking of GPT-4 Turbo or GPT-4o, which were OpenAI’s previous generation models before GPT-5.
The Bottom Line
GPT-5.1-Codex-Max is currently one of the best coding models available, particularly for long-running, complex software engineering tasks. It outperforms earlier models on most coding benchmarks and can handle tasks that would have previously failed due to context limitations.