OpenAIGPT-5.5VSxAIGrok 4.20
Our Take
We recommend GPT-5.5 if you need peak intelligence for reasoning and coding tasks, or the 3.8x cheaper Grok 4.20 to optimize your budget for high-volume pipelines. While GPT-5.5 holds a clear performance lead, it carries a heavy price premium. Choose GPT-5.5 for complex logic, or Grok 4.20 for budget efficiency.
▶WHY?
Benchmark Calculations & Evidence:
Coding Benchmarks: Both models were evaluated on the SWE-bench Pro benchmark. GPT-5.5 scored 58.6%, while Grok 4.20 scored 51.8%.
Reasoning Benchmarks: Both models were evaluated on the GPQA Diamond benchmark. GPT-5.5 scored 93.6%, while Grok 4.20 scored 90%.
Cost Efficiency: Grok 4.20 pricing ($2/M input, $6/M output) is 3.8x cheaper than GPT-5.5 ($5/M input, $30/M output).
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Benchmarks & Scores
Coding (swe-bench-pro)Winner (+6.8%)
58.6%complex codebases, multi-file repositories, and architectural planning
Reasoning (gpqa-diamond)Winner (+3.6%)
93.6%graduate-level science QA
Cost & Context
Cost (per 1M tokens)
$11.25Input: $5.00 | Output: $30.00Context WindowLarger
1.05M tokensBenchmarks & Scores
Coding (swe-bench-pro)
51.8%complex codebases, multi-file repositories, and architectural planning
Reasoning (gpqa-diamond)
90%graduate-level science QA
Cost & Context
Cost (per 1M tokens)3.8x cheaper
$3.00Input: $2.00 | Output: $6.00Context Window
1.05M tokensFrequently Asked Questions about GPT-5.5 vs Grok 4.20
Grok 4.20 is cheaper than GPT-5.5. Grok 4.20 has a blended cost of $3.00/1M tokens, which is about 3.8x cheaper than GPT-5.5 at $11.25/1M tokens.
GPT-5.5 is better for coding tasks on this benchmark. It scores 58.6% on swe-bench-pro (complex codebases, multi-file repositories, and architectural planning) compared to Grok 4.20 which scores 51.8%.
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