IQ of SI
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Automated page. Written and translated automatically by AI and checked against the sources by software; no human editor. SI-IQ is an index built from public benchmark results, not an IQ test. How it works

Claude Opus 5.5 vs GPT-6 Sol: which is smarter?

Claude Opus 5.5 has an SI-IQ of 144 and GPT-6 Sol has 140. The table compares them area by area using only independent benchmark results.

Data as of Oct 18, 2026 · method 1.0.0

MetricClaude Opus 5.5GPT-6 Sol
SI-IQ144141–148140137–144
Reasoning146139
Math145143
Knowledge137138
DeveloperAnthropicOpenAI
ReleasedSep 22, 2026Sep 22, 2026
AccessAPI accessAPI access
Price in / out (USD per 1M tokens)$4.00 / $20$2.00 / $10
Benchmarks used99
Claude Opus 5.5GPT-6 Sol
130140150SI-IQReasoningMathKnowledge

Benchmarks every compared model was tested on

Raw scores as published by the evaluators.

BenchmarkClaude Opus 5.5GPT-6 Sol
Chess Puzzles67.0%56.0%
FrontierMath Tier 495.0%90.0%
FrontierMath Tiers 1–391.2%89.8%
Furniture Assembly83.3%58.3%
GPQA Diamond90.6%94.3%
GPQA Diamond (OpenRouter run)90.2%92.1%
Mystery Game Puzzles71.0%56.0%
OTIS Mock AIME 2024–2025100.0%100.0%
SimpleQA Verified72.2%60.7%
τ²-bench Airline (OpenRouter run)75.6%70.2%

The difference of 4 points is within the statistical uncertainty: the two models are roughly on par.

Data sources: Arena leaderboard dataset on Hugging Face (CC BY 4.0); Epoch AI, ‘Capabilities & benchmarking’ (CC BY 4.0); LiteLLM, model_prices_and_context_window.json (MIT); Source: OpenRouter (openrouter.ai), licensed under CC BY 4.0: reuse and republish with attribution to OpenRouter (licences and changes).