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Model comparison

Gemini 3 Pro vs Grok 4.20

Data verified

Head-to-head evidence from 5 shared benchmark results across 4 categories. Overall scores shown here use the public BenchAlign v5 ranking lane.

66.85/100
Margin
13.0pts
← winning
53.88/100
1 category wins1 category wins

Public leaderboard positions: Gemini 3 Pro #21 (Supported); Grok 4.20 #93 (Estimated). Intervals and evidence labels describe ranking uncertainty, not a guarantee for a specific workload.

Evidence parity. Gemini 3 Pro and Grok 4.20 share 5 comparable benchmark results. 2 of 8 categories are comparable. 22 results are unique to Gemini 3 Pro; 14 to Grok 4.20.

Updated July 28, 2026
Shared results
5
Gemini 3 Pro only
22
Grok 4.20 only
14
Comparable categories
2 / 8

Pick Gemini 3 Pro if you want the stronger benchmark profile. Grok 4.20 only becomes the better choice if reasoning is the priority or you want the cheaper token bill.

Confidence note. This is a partial-evidence comparison with 5 shared benchmark results across 4 evidence categories; 2 of 8 categories currently have scoreable aggregates for both models. Treat the verdict as directional until coverage is more balanced.

Why this result

Gemini 3 Pro is clearly ahead on the BenchAlign aggregate, 66.85 to 53.88. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.

Gemini 3 Pro's sharpest advantage is in multimodal & grounded, where it averages 81.1 against 70.1. The single biggest benchmark swing on the page is ARC-AGI-2, 31.1% to 53.3%. Grok 4.20 does hit back in reasoning, so the answer changes if that is the part of the workload you care about most.

Gemini 3 Pro is also the more expensive model on tokens at $2.00 input / $12.00 output per 1M tokens, versus $2.00 input / $6.00 output per 1M tokens for Grok 4.20. That is roughly 2.0x on output cost alone. Grok 4.20 is the reasoning model in the pair, while Gemini 3 Pro is not. That usually helps on harder chain-of-thought-heavy tests, but it can also mean more latency and more token spend in real use.

Category breakdown

Exact category averages are shown below. Not measured means BenchLM does not have enough sourced public coverage for that model and category.

Category scores and score margins for Gemini 3 Pro and Grok 4.20
CategoryGemini 3 ProΔGrok 4.20
ReasoningGemini 3 Pro31.1Margin→ 22.2Grok 4.2053.3
MultimodalGemini 3 Pro81.1Margin← 11.0Grok 4.2070.1
AgenticGemini 3 ProNot measuredMarginNo overlapGrok 4.2047.1
CodingGemini 3 ProNot measuredMarginNo overlapGrok 4.2067.1
MathGemini 3 Pro32.9MarginNo overlapGrok 4.20Not measured

Decisive benchmark drivers

The largest measured benchmark gaps in this matchup, with exact reported values.

More
A · Gemini 3 ProB · Grok 4.20

  1. ARC-AGI-2

    Reasoning
    Source ↗
    A 31.1%B 53.3%
    Winner: Grok 4.20Δ 22.2
    ARC-AGI-2: Gemini 3 Pro scored 31.1%; Grok 4.20 scored 53.3%. Grok 4.20 wins this benchmark.

  2. CharXiv

    Multimodal
    Source ↗
    A 81.4%B 60.9%
    Winner: Gemini 3 ProΔ 20.5
    CharXiv: Gemini 3 Pro scored 81.4%; Grok 4.20 scored 60.9%. Gemini 3 Pro wins this benchmark.

  3. MMMU-Pro

    Multimodal
    Source ↗
    A 81%B 75.2%
    Winner: Gemini 3 ProΔ 5.8
    MMMU-Pro: Gemini 3 Pro scored 81%; Grok 4.20 scored 75.2%. Gemini 3 Pro wins this benchmark.

Operational comparison

Runtime and commercial metrics are compared only when both models have a complete sourced value.

MetricGemini 3 ProGrok 4.20Comparison
Input / output priceUSD per 1M tokensGemini 3 Pro$2 input / $12 outputGrok 4.20$2 input / $6 outputGrok 4.20 has the lower combined listed price.
Generation speedtokens per secondGemini 3 Pro109 tok/sGrok 4.20233 tok/sGrok 4.20 has the higher measured throughput.
First-answer latencyseconds to first tokenGemini 3 Pro32.65 sGrok 4.2010.33 sGrok 4.20 reaches the first token sooner.
Context windowmaximum listed tokensGemini 3 Pro2MGrok 4.202MListed context windows are equal.

Benchmark Deep Dive

Agentic
BenchmarkGemini 3 ProGrok 4.20Result
τ²-bench resultsSource 87.1%—Not comparable
Gert LabsSource 63.23%38.36%Gemini 3 Pro leads
JobBenchSource 11.4%—Not comparable
Terminal-Bench 2.0Source —47.1%Not comparable
DeepSearchQASource —62.8%Not comparable
Coding
BenchmarkGemini 3 ProGrok 4.20Result
Vibe Code BenchSource 14.30%4.06%Gemini 3 Pro leads
AA-SciCodeSource 56.1%—Not comparable
AA LiveCodeBenchSource 91.7%—Not comparable
LiveCodeBench ProSource —74.2%Not comparable
SWE-bench VerifiedSource —76.7%Not comparable
SWE-bench ProSource —51.8%Not comparable
ReasoningGrok 4.20 wins
BenchmarkGemini 3 ProGrok 4.20Result
ARC-AGI-2Source 31.1%53.3%Grok 4.20 leads
AA-LCRSource 70.7%—Not comparable
CritPtSource 9.1%—Not comparable
ARC-AGI-3Source —0.1%Not comparable
Knowledge
BenchmarkGemini 3 ProGrok 4.20Result
Artificial Analysis Intelligence IndexSource 39.5%—Not comparable
AA-GPQA DiamondSource 90.8%—Not comparable
AA-HLESource 37.2%—Not comparable
AA-Omniscience IndexSource 15.8%—Not comparable
AA-Omniscience AccuracySource 55.9%—Not comparable
AA-Omniscience Hallucination RateSource 90.9%—Not comparable
AA MMLU-ProSource 89.8%—Not comparable
GPQA-DSource —88.5%Not comparable
HLE w/o toolsSource —31.6%Not comparable
HealthBench HardSource —20.3%Not comparable
MedXpertQA (Text)Source —50.2%Not comparable
Math
BenchmarkGemini 3 ProGrok 4.20Result
FrontierMath v2 (Tiers 1-3)Source 37.600%—Not comparable
FrontierMath v2 (Tier 4)Source 18.750%—Not comparable
Multilingual
BenchmarkGemini 3 ProGrok 4.20Result
AA Global-MMLU-LiteSource 92.2%—Not comparable
MultimodalGemini 3 Pro wins
BenchmarkGemini 3 ProGrok 4.20Result
MMMU-ProSource 81%75.2%Gemini 3 Pro leads
MathVisionSource 86.6%—Not comparable
VideoMMMUSource 87.6%—Not comparable
ScreenSpot ProSource 72.7%—Not comparable
CharXivSource 81.4%60.9%Gemini 3 Pro leads
V*Source 88.0%—Not comparable
AA-MMMU-ProSource 80.2%—Not comparable
ERQASource —54.1%Not comparable
SimpleVQASource —57.4%Not comparable
MedXpertQA (MM)Source —65.8%Not comparable
Design Arena WebsiteSource —1252Not comparable
Inst. Following
BenchmarkGemini 3 ProGrok 4.20Result
AA-IFBenchSource 70.4%—Not comparable
Frequently Asked Questions (3)

Which is better, Gemini 3 Pro or Grok 4.20?

Gemini 3 Pro is ahead on BenchLM's BenchAlign leaderboard, 66.85 to 53.88. The biggest single separator in this matchup is ARC-AGI-2, where the scores are 31.1% and 53.3%.

Which is better for reasoning, Gemini 3 Pro or Grok 4.20?

Grok 4.20 has the edge for reasoning in this comparison, averaging 53.3 versus 31.1. Inside this category, ARC-AGI-2 is the benchmark that creates the most daylight between them.

Which is better for multimodal and grounded tasks, Gemini 3 Pro or Grok 4.20?

Gemini 3 Pro has the edge for multimodal and grounded tasks in this comparison, averaging 81.1 versus 70.1. Inside this category, CharXiv is the benchmark that creates the most daylight between them.

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Last updated: July 28, 2026

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