GoogleGemini 3.5 FlashVSxAIGrok 4.20
Our Take
We recommend Gemini 3.5 Flash for its clear benchmark advantage, or the 1.1x cheaper Grok 4.20 only if your budget requires optimizing costs for very high-volume pipelines. While Gemini 3.5 Flash offers superior reasoning and coding, it carries a moderate price premium. Choose Gemini 3.5 Flash for quality, or Grok 4.20 for cost optimization.
▶WHY?
Benchmark Calculations & Evidence:
Coding Benchmarks: Both models were evaluated on the SWE-bench Pro benchmark. Gemini 3.5 Flash scored 55.1%, while Grok 4.20 scored 51.8%.
Reasoning Benchmarks: Both models were evaluated on the GPQA Diamond benchmark. Gemini 3.5 Flash scored 92.2%, while Grok 4.20 scored 90%.
Cost Efficiency: Grok 4.20 pricing ($2/M input, $6/M output) is 1.1x cheaper than Gemini 3.5 Flash ($1.5/M input, $9/M output).
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Benchmarks & Scores
Coding (swe-bench-pro)Winner (+3.3%)
55.1%complex codebases, multi-file repositories, and architectural planning
Reasoning (gpqa-diamond)Winner (+2.2%)
92.2%graduate-level science QA
Cost & Context
Cost (per 1M tokens)
$3.38Input: $1.50 | Output: $9.00Context Window
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)1.1x cheaper
$3.00Input: $2.00 | Output: $6.00Context Window
1.05M tokensFrequently Asked Questions about Gemini 3.5 Flash vs Grok 4.20
Grok 4.20 is cheaper than Gemini 3.5 Flash. Grok 4.20 has a blended cost of $3.00/1M tokens, which is about 1.1x cheaper than Gemini 3.5 Flash at $3.38/1M tokens.
Gemini 3.5 Flash is better for coding tasks on this benchmark. It scores 55.1% 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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