GPT-5.5 vs Grok 4.20

GPT-5.5 against Grok 4.20
GPT-5.5Grok 4.20
Coding index71.333.3
Benchmarks behind it Verified, 5 benchmarks Partial, 2 benchmarks
Output $/Mtok$30.00$2.50
Cost per solved task$1.65$0.72
Context window1.05M2M