Noometry

Model comparison

Gemini 3.5 Flash vs Grok 4.20 (Non-Reasoning)

Gemini 3.5 Flash is the stronger model overall, scoring 54.1 to 48.5 on the Noometry Index. Grok 4.20 (Non-Reasoning) costs 2.2× less per token, which makes it the better buy when Gemini 3.5 Flash's lead doesn't matter for your workload.

Last verified . 38 shared benchmarks.

Gemini 3.5 Flash Google

54.1

Rank #29 Confirmed

Grok 4.20 (Non-Reasoning) xAI

48.5

Rank #48 Confirmed

Summary

  • They share 38 benchmarks with published results for both. Gemini 3.5 Flash scores higher in 7 categories and Grok 4.20 (Non-Reasoning) in 3 categories; 8 gaps are clear of the uncertainty.
  • The widest gap is in knowledge, where Gemini 3.5 Flash leads 66.3 to 52.8.
  • The biggest single-benchmark swing is SimpleQA Verified: 66.2% for Gemini 3.5 Flash and 30.2% for Grok 4.20 (Non-Reasoning).
  • Grok 4.20 (Non-Reasoning) is cheaper at $1.25 / $2.50 per million input/output tokens, against $1.50 / $9 for Gemini 3.5 Flash.
  • Gemini 3.5 Flash accepts more context: 1.05M tokens versus 1M.

Side by side

Gemini 3.5 FlashGrok 4.20 (Non-Reasoning)
ProviderGooglexAI
Noometry Index54.148.5
Released2026-05-192026-02-17
WeightsProprietaryProprietary
Context window1.05M1M
Max output66K30K
Input $ / M tokens$1.50$1.25
Output $ / M tokens$9$2.50
Results tracked5446

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Category by category

Coding Gemini 3.5 Flash leads

Gemini 3.5 Flash: 49.1 (#46), Grok 4.20 (Non-Reasoning): 41.8 (#104)

BenchmarkGemini 3.5 FlashGrok 4.20 (Non-Reasoning)
LMArena WebDev14991374
WeirdML62.6%52.3%
LMArena Coding14921458
ALE-Bench911.021,150
SWE-bench Verified79.3%—
DeepSWE37.4%—
SciCode53.1%—

Agentic & Tool Use Grok 4.20 (Non-Reasoning) leads

Gemini 3.5 Flash: 24.8 (#107), Grok 4.20 (Non-Reasoning): 34.3 (#43)

BenchmarkGemini 3.5 FlashGrok 4.20 (Non-Reasoning)
Vending-Bench 25,3964,663
Terminal-Bench—57.3%
APEX-Agents27.5%—
τ²-bench Banking—18%
GBAEval6.7%—
GDP.pdf14%—
LMArena Search—1189

Reasoning Gemini 3.5 Flash leads

Gemini 3.5 Flash: 62.7 (#16), Grok 4.20 (Non-Reasoning): 52.2 (#30)

BenchmarkGemini 3.5 FlashGrok 4.20 (Non-Reasoning)
ARC-AGI-272.1%65.1%
NYT Connections (extended)92.6%85.4%
ARC-AGI-192.5%89.5%
Chess Puzzles50%24%
LMArena Hard Prompts14881451
DTBench94.7%90.1%
LMCA47.1%38.7%
Epoch Capabilities Index154.55152.01
ForecastBench5961.4
SimpleBench76.7%—
Kagi LLM Benchmark—75%
CritPt13.1%—
EnigmaEval25.4%—
Thematic Generalization—63.8%
EBR-Bench4.8%—
Mystery Game Puzzles32%—
Surface Evolver Bench58.1%—

Math Gemini 3.5 Flash leads

Gemini 3.5 Flash: 60.5 (#30), Grok 4.20 (Non-Reasoning): 48.0 (#54)

BenchmarkGemini 3.5 FlashGrok 4.20 (Non-Reasoning)
FrontierMath (Tiers 1-3)62.8%44.9%
FrontierMath Tier 426.8%17.1%
OTIS Mock AIME 2024-202595.6%92.2%
ProofBench31%14%
LMArena Math15021455
MathArena Final-Answer Competitions76.3%—
FrontierMath (Feb 2025 set)39%—
FrontierMath Tier 4 (v1)14.6%—

Knowledge Gemini 3.5 Flash leads

Gemini 3.5 Flash: 66.3 (#10), Grok 4.20 (Non-Reasoning): 52.8 (#54)

BenchmarkGemini 3.5 FlashGrok 4.20 (Non-Reasoning)
GPQA Diamond92.8%89.3%
SimpleQA Verified66.2%30.2%
LMArena Expert14931440

Multimodal Gemini 3.5 Flash leads

Gemini 3.5 Flash: 45.7 (#13), Grok 4.20 (Non-Reasoning): 33.2 (#88)

BenchmarkGemini 3.5 FlashGrok 4.20 (Non-Reasoning)
LMArena Vision13111263
Blueprint-Bench 233.6%0%
LMArena Document14631416

Multilingual Gemini 3.5 Flash leads

Gemini 3.5 Flash: 57.1 (#12), Grok 4.20 (Non-Reasoning): 54.7 (#38)

BenchmarkGemini 3.5 FlashGrok 4.20 (Non-Reasoning)
LMArena Non-English14751440
LMArena Chinese15251481
LMArena French14901477
LMArena German15001463
LMArena Japanese14811450
LMArena Korean14531417
LMArena Russian14911457
LMArena Spanish14781442

Instruction Following Gemini 3.5 Flash leads

Gemini 3.5 Flash: 77.2 (#29), Grok 4.20 (Non-Reasoning): 75.0 (#79)

BenchmarkGemini 3.5 FlashGrok 4.20 (Non-Reasoning)
LMArena Instruction Following14661420

Long Context Too close to call

Gemini 3.5 Flash: 45.3 (#39), Grok 4.20 (Non-Reasoning): 45.4 (#33)

BenchmarkGemini 3.5 FlashGrok 4.20 (Non-Reasoning)
LMArena Longer Query14811436
CL-bench—22.2%
CL-bench Life—11.9%

Writing & Preference Too close to call

Gemini 3.5 Flash: 65.5 (#46), Grok 4.20 (Non-Reasoning): 65.9 (#42)

BenchmarkGemini 3.5 FlashGrok 4.20 (Non-Reasoning)
LMArena Text14811451
LMArena Creative Writing14671439
LMArena Multi-Turn14821456
EQ-Bench Creative Writing—1574
EQ-Bench 41087—

Frequently asked questions

Is Gemini 3.5 Flash better than Grok 4.20 (Non-Reasoning)?

Gemini 3.5 Flash is the stronger model overall, scoring 54.1 to 48.5 on the Noometry Index. Grok 4.20 (Non-Reasoning) costs 2.2× less per token, which makes it the better buy when Gemini 3.5 Flash's lead doesn't matter for your workload.

Which is cheaper, Gemini 3.5 Flash or Grok 4.20 (Non-Reasoning)?

Grok 4.20 (Non-Reasoning) is cheaper. It lists at $1.25 per million input tokens and $2.50 per million output tokens; Gemini 3.5 Flash lists at $1.50 and $9.

Is Gemini 3.5 Flash or Grok 4.20 (Non-Reasoning) better for coding?

Gemini 3.5 Flash scores higher on coding benchmarks: 49.1 versus 41.8 in the Noometry coding category.

Which has the bigger context window?

Gemini 3.5 Flash does, with 1.05M tokens against 1M.

How many benchmarks do Gemini 3.5 Flash and Grok 4.20 (Non-Reasoning) share?

38 benchmarks have published results for both models. Gemini 3.5 Flash has 54 scored results on Noometry and Grok 4.20 (Non-Reasoning) has 46.

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