GPT-5.5 Pro vs Claude Opus 4.7: Real-World Performance Test 2026
## Table of Contents 1. [Introduction](#introduction) 2. [Benchmark Methodology](#benchmark-methodology) 3. [Reasoning & Math Performance](#reasoning–math-performance) 4. [Coding Tasks](#coding-tasks) 5. [Creative Writing](#creative-writing) 6. [Context Window & Memory](#context-window–memory) 7. [Speed & Latency](#speed–latency) 8. [Pricing Comparison](#pricing-comparison) 9. [Who Should Use What](#who-should-use-what) 10. [Conclusion](#conclusion) — ## Introduction Two AI giants are fighting for dominance in 2026: **GPT-5.5 Pro** from OpenAI and **Claude Opus 4.7** from Anthropic. Both models claim to be the most powerful, but what’s the real difference when you put them to work? I spent three weeks testing both models across 47 real-world tasks — from complex coding problems to creative writing, from