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GPT-5 Codex vs GPT-5.1 Thinking
Comprehensive side-by-side LLM comparison
GPT-5.1 Thinking leads with 1.8% higher average benchmark score. GPT-5.1 Thinking supports multimodal inputs. Both models have their strengths depending on your specific coding needs.
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OpenAI
GPT-5 Codex, released by OpenAI in August 2025, is a coding-specialized large language model from the GPT-5 family engineered for software engineering, code generation, and agentic development workflows. It builds on GPT-5's architecture with optimizations targeting multi-file code editing, test generation, and automated debugging. GPT-5 Codex targets developers and agentic coding tools requiring a model tuned specifically for programming tasks.
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OpenAI
GPT-5.1 Thinking, released by OpenAI in November 2025, is an extended reasoning variant from the GPT-5.1 family that applies chain-of-thought processing to improve accuracy on complex reasoning, mathematics, and coding tasks. It targets analytical workflows where deliberate reasoning over a problem significantly improves output quality.
3 months newer
GPT-5 Codex
OpenAI
2025-08
GPT-5.1 Thinking
OpenAI
2025-11
Average performance across 1 common benchmarks
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GPT-5 Codex
Average Score:74.5%
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GPT-5.1 Thinking
Average Score:76.3%(+1.8%)
Performance comparison across key benchmark categories
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GPT-5 Codex
Coding74.5%
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GPT-5.1 Thinking
Coding76.3%(+1.8%)
Provider Availability & Performance
Available providers and their performance metrics
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GPT-5 Codex
0 providers
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GPT-5.1 Thinking
0 providers
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GPT-5 Codex
Avg Score:74.5%
Providers:0
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GPT-5.1 Thinking
Avg Score:76.3%(+1.8%)
Providers:0