# Gemini 4 Carbon Scores 69.1% to Lead HLE-Diamond Ranking By Simon Yoon Canonical URL: https://www.tokenpost.com/news/technology/44147 Published: 2026-10-30T02:28:46.000Z Updated: 2026-10-30T02:28:46.000Z Section: Technology > The model leads both reasoning and knowledge sections. A separate Index v5 ranking was published before Google announced Carbon. Gemini 4 Carbon (High) tops the current HLE-Diamond ranking with a 69.1% score, ahead of Claude Opus 5.5 (Max, Default Fallback) at 67.9%, giving Google’s model the highest listed result on this academic benchmark. Claude Opus 5.5 (Xhigh, Default Fallback) scored 64.0%. Carbon also leads the ranking’s two sections, with 79.6% on reasoning and 58.6% on knowledge. The Max, Default Fallback Claude configuration scored 78.0% on reasoning and 57.8% on knowledge, leaving the models separated by 1.6 percentage points in reasoning and 0.8 points in knowledge. HLE-Diamond contains 1,000 questions, split evenly between reasoning and knowledge, and 272 questions include images. The evaluation runs without tools and allows one answer per question. GPT-5.6 Luna (medium) judges the responses. The test focuses on closed-ended academic questions, so a leading score measures performance on that task set rather than a model’s ability to conduct open-ended research. HLE-Diamond is a refined subset of Humanity’s Last Exam. The Center for AI Safety and Scale AI released it Sept. 22 after a year of refining questions. The organizations cautioned that high accuracy alone would not demonstrate autonomous research ability or artificial general intelligence. Index v5, published Tuesday, Oct. 27, offers a separate, broader comparison. It ranked Claude Opus 5.5 first overall at 58, followed by GPT-6 Astra at 57 and GPT-6.1 Sol at 55. HLE-Diamond accounts for 10% of the index’s General category, which makes up 25% of the full index. Google announced Gemini 4 Carbon Wednesday, Oct. 28, one day after the index release, so those overall rankings do not include Carbon. The HLE-Diamond result is a single-benchmark comparison. Its ranking focuses on a fixed question set, while Index v5 combines several categories. The two results therefore measure different ranges of model performance. Google’s [staged rollout](), announced Wednesday, Oct. 28, starts with some cyber defenders and is set to expand to trusted partners. The company gave no date for general access. ## Links in this article - [staged rollout](https://www.tokenpost.com/news/technology/43070)