Head-to-head comparison across 4benchmark categories. Overall scores shown here use BenchLM's provisional ranking lane.
Gemini 3.5 Flash
88
Grok 4.20
64
Verified leaderboard positions: Gemini 3.5 Flash #7 · Grok 4.20 unranked
Pick Gemini 3.5 Flash if you want the stronger benchmark profile. Grok 4.20 only becomes the better choice if coding is the priority or you want the cheaper token bill.
Agentic
+30.1 difference
Coding
+6.5 difference
Reasoning
+21.4 difference
Multimodal
+13.0 difference
Gemini 3.5 Flash
Grok 4.20
$1.5 / $9
$2 / $6
284.2 t/s
233 t/s
18.55s
10.33s
1M
2M
Pick Gemini 3.5 Flash if you want the stronger benchmark profile. Grok 4.20 only becomes the better choice if coding is the priority or you want the cheaper token bill.
Gemini 3.5 Flash is clearly ahead on the provisional aggregate, 88 to 64. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.
Gemini 3.5 Flash's sharpest advantage is in agentic, where it averages 77.2 against 47.1. The single biggest benchmark swing on the page is Terminal-Bench 2.0, 76.2% to 47.1%. Grok 4.20 does hit back in coding, so the answer changes if that is the part of the workload you care about most.
Gemini 3.5 Flash is also the more expensive model on tokens at $1.50 input / $9.00 output per 1M tokens, versus $2.00 input / $6.00 output per 1M tokens for Grok 4.20. Grok 4.20 gives you the larger context window at 2M, compared with 1M for Gemini 3.5 Flash.
Gemini 3.5 Flash is ahead on BenchLM's provisional leaderboard, 88 to 64. The biggest single separator in this matchup is Terminal-Bench 2.0, where the scores are 76.2% and 47.1%.
Grok 4.20 has the edge for coding in this comparison, averaging 61 versus 54.5. Inside this category, SWE-bench Pro is the benchmark that creates the most daylight between them.
Gemini 3.5 Flash has the edge for reasoning in this comparison, averaging 74.7 versus 53.3. Inside this category, ARC-AGI-2 is the benchmark that creates the most daylight between them.
Gemini 3.5 Flash has the edge for agentic tasks in this comparison, averaging 77.2 versus 47.1. Inside this category, Terminal-Bench 2.0 is the benchmark that creates the most daylight between them.
Gemini 3.5 Flash has the edge for multimodal and grounded tasks in this comparison, averaging 83.8 versus 70.8. Inside this category, CharXiv is the benchmark that creates the most daylight between them.
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