Realworld benchmark between Codex 5.3 and Opus 4.6 (swe-agi.com)

A recent benchmark comparison between OpenAI's GPT-5.3 Codex and Anthropic's Claude Opus 4.6 showcases significant advancements in AI code generation capabilities. The study evaluated six models across 22 tasks, revealing that GPT-5.3 Codex outperformed its counterparts, successfully completing 19 of 22 tasks with a remarkable test case pass rate of 95.6%. Notably, GPT-5.3 achieved this in just 24.8 hours at a cost of $213.07, significantly more efficiently compared to Claude Opus 4.6, which passed only 15 tasks at a higher expense and longer time commitment. This benchmark is crucial for the AI/ML community as it highlights the continuing evolution of generative models in code tasks, particularly in handling varying levels of difficulty. GPT-5.3 showcased consistent top performance across all difficulty tiers, with a perfect success rate in the easy tier, while Claude Opus 4.6 improved its performance over its predecessor but still lagged behind. The results emphasize the importance of efficiency and cost-effectiveness in real-world applications, suggesting that advancements in model architecture and training methodologies will be key to enhancing the capabilities of AI in programming tasks.