Verdict
Evenly split 5–5 across 10 shared benchmarks.
GPT-5.1 5 · Grok 4.20 5 · higher isn't always better — check the caveats below.
Reported scores — protocols may differ. How we compare
Reasoning: Grok 4.20 leads 2–1 across 3 shared reasoning benchmarks (largest gap: ARC-AGI, 89.5 vs 72.83 — single evaluator).
Context Learning: GPT-5.1 leads 2–0 across 2 shared context learning benchmarks (largest gap: CL-bench Life, 17.3 vs 11.9 — protocols undisclosed).
Evenly split 5–5 across 10 shared benchmarks. GPT-5.1 leads 5 benchmarks and Grok 4.20 leads 5. Higher isn't always better — see the integrity caveats on each benchmark.
GPT-5.1 and Grok 4.20 have 10 benchmarks in common in our data — those are the only rows where a direct, apples-to-apples comparison is drawn.
GPT-5.1 leads context learning 2–0. Grok 4.20 leads reasoning 2–1.