Artificial Analysis v5 widens proprietary-open-weight AI gap to 12 points

Artificial Analysis released its v5 Intelligence Index, shifting 60% of the score to private held-out tests and agentic tasks. The margin between the best proprietary and best open-weight model grew from 3 to 12 points. Claude Opus 5.5 leads at 58, GPT-6 Astra at 57, and Kimi K3.1 Pro at 46.

• Claude Opus 5.5 scores 58, GPT-6 Astra 57, GPT-6.1 Sol 55
• Kimi K3.1 Pro reaches 46, 12 points behind the leader
• 60% of the index now rests on private tests, up from 45% in v4.3
• Median output tokens per task rose from 35,000 to 59,000