Artificial Analysis says that one year ago GPT-5 mini (high) led its Intelligence Index at 17 on v4.3 and about $0.05 per task. As of last week, Claude Opus 5.5 holds the highest score to date at 58 and about $5.98 per task.
OpenRouter had claude-opus-5.5 grade every run of its openrouter-decisions skill against a fixed checklist. In a blind comparison, Opus picked the skill version of each task all 36 times.
On Ibragim’s my-mini-bench in pi, Sonnet 5.5 and Opus 5.5 High both passed 30 of 30 runs. Sonnet 5.5 took 46 seconds and $0.10 per task, versus 103 seconds and $0.30 for Opus 5.5 High.
Cline says Sonnet 5.5 beats Opus 5.5 on Terminal-Bench 4.0 while costing half as much. Cline also says it uses fewer tokens than earlier models, cuts cost by up to 30% per task, and generates output 30% faster than its predecessor.
Arena.ai ranks Claude Opus 5.5 (High) No. 2 in Agent Arena, with a +12.15% net improvement at a $1.31 median cost per task. It scores above Opus 5 (Max) and Opus 5 (High) while costing 40–56% less.
Arena.ai says Claude Opus 5.5 (High) leads Text Arena with 1,509 points, 18 above Opus 5 (High) and 4 above second-place Opus 4.6 (High). It also says Anthropic holds all six top spots and that Opus 5.5 (High) is on the Pareto frontier at a blended $16 per million tokens.
Arena.ai says it has generated side-by-side outputs from Anthropic’s Claude Opus 5.5 and OpenAI’s GPT-6 Sol, and that scores for Claude Opus 5.5 are coming soon.
Anthropic said on September 22, 2026, that Claude Opus 5.5 is available. Claude says it performs at the level of Claude Fable 5.1 for most tasks and costs 40% less to run than Opus 5.
