Grok 4.5, developed by xAI, has placed fourth on the Artificial Analysis Intelligence Index with a score of 54, trailing only Claude Fable 5, GPT-5.5, and Claude Opus 4.8, marking a 16-point jump from Grok 4.3's score of 38. On the GDPval-AA v2 benchmark, Grok 4.5 scored an Elo of 1543, sitting between Claude Opus 4.8 at 1600 and GLM-5.2 at 1513. On τ³-Banking, a test of agentic customer service, Grok 4.5 posted the highest score at 33%, edging out GPT-5.5 (xhigh) at 31%. Grok 4.5 also topped AutomationBench-AA, completing 51.4% of task objectives cleanly, ahead of Claude Fable 5 at 48.6% and Claude Opus 4.8 at 48.5%, while using roughly 8,000 output tokens per task. The model runs at $0.31 per task on the Intelligence Index, cheaper than GLM-5.2 and Kimi K2.6, and roughly a fifth of what Claude Sonnet 5 (max) costs. On GDPval-AA v2, its cost per task is $0.49, nearly 90% below the models