Verdict
GPT-5.6 Sol leads 14–4 across 18 shared benchmarks.
Gemini 3.1 Pro 4 · GPT-5.6 Sol 14 · higher isn't always better — check the caveats below.
Reported scores — protocols may differ. How we compare
Reasoning: Gemini 3.1 Pro leads 4–0 across 4 shared reasoning benchmarks (largest gap: SimpleBench, 75.52 vs 66.04 — single evaluator).
Unknown: GPT-5.6 Sol leads 3–0 across 3 shared unknown benchmarks (largest gap: ProofBench, 83 vs 26 — single evaluator).
Coding: GPT-5.6 Sol leads 2–0 across 2 shared coding benchmarks (largest gap: DeepSWE, 72.67 vs 11.75 — single evaluator).
Math: GPT-5.6 Sol leads 2–0 across 2 shared math benchmarks (largest gap: FrontierMath-Tier-4-v2-Private, 82.93 vs 26.83 — single evaluator).
Vendor claims — compare against the measured scores above. A claim is what a developer says about its own model, not an independent measurement.
Agentic / Tool Use
“Gemini 3.1 Pro was evaluated across a range of benchmarks, including reasoning, multimodal capabilities, agentic tool use, multi-lingual performance, and long-context.”
Multimodal
“a suite of highly capable, natively multimodal reasoning models”
Reasoning
“Gemini 3.1 Pro is Google's most advanced model for complex tasks.”
No vendor claims on file for GPT-5.6 Sol.
GPT-5.6 Sol leads 14–4 across 18 shared benchmarks. Gemini 3.1 Pro leads 4 benchmarks and GPT-5.6 Sol leads 14. Higher isn't always better — see the integrity caveats on each benchmark.
Gemini 3.1 Pro 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.
Gemini 3.1 Pro leads reasoning 4–0. GPT-5.6 Sol leads unknown 3–0.