Verdict
Claude Opus 5.5 leads 15–2 across 18 shared benchmarks.
Claude Opus 5.5 15 · GPT-5.6 Sol 2 · 1 tied · higher isn't always better — check the caveats below.
Reported scores — protocols may differ. How we compare
Unknown: Claude Opus 5.5 leads 6–0 across 6 shared unknown benchmarks (largest gap: Furniture Assembly, 76.19 vs 38.1 — protocols undisclosed).
Coding: Claude Opus 5.5 leads 3–0 across 3 shared coding benchmarks (largest gap: MirrorCode, 77.4 vs 20 — protocols undisclosed).
Reasoning: Claude Opus 5.5 leads 2–1 across 3 shared reasoning benchmarks (largest gap: GPQA diamond, 91.33 vs 87.46 — protocols undisclosed).
Math: Claude Opus 5.5 leads 1–0 across 2 shared math benchmarks (largest gap: FrontierMath-Tier-4-v2-Private, 95 vs 82.93 — protocols undisclosed).
Claude Opus 5.5 leads 15–2 across 18 shared benchmarks. Claude Opus 5.5 leads 15 benchmarks and GPT-5.6 Sol leads 2, with 1 tied. Higher isn't always better — see the integrity caveats on each benchmark.
Claude Opus 5.5 and GPT-5.6 Sol have 18 benchmarks in common in our data — those are the only rows where a direct, apples-to-apples comparison is drawn.
Claude Opus 5.5 leads unknown 6–0. Claude Opus 5.5 leads coding 3–0.