Model comparison
Gemini 3.5 Flash vs Grok 4 Fast
Gemini 3.5 Flash is the stronger model overall, scoring 54.1 to 39.0 on the Noometry Index.
Last verified . 24 shared benchmarks.
GoogleSummary
- They share 24 benchmarks with published results for both. Gemini 3.5 Flash scores higher in 7 categories and Grok 4 Fast in 2 categories; 9 gaps are clear of the uncertainty.
- The widest gap is in reasoning, where Gemini 3.5 Flash leads 62.7 to 22.5.
- The biggest single-benchmark swing is ARC-AGI-2: 72.1% for Gemini 3.5 Flash and 5.3% for Grok 4 Fast.
Side by side
| Gemini 3.5 Flash | Grok 4 Fast | |
|---|---|---|
| Provider | xAI | |
| Noometry Index | 54.1 | 39.0 |
| Released | 2026-05-19 | 2025-09-19 |
| Weights | Proprietary | Proprietary |
| Context window | 1.05M | — |
| Max output | 66K | — |
| Input $ / M tokens | $1.50 | — |
| Output $ / M tokens | $9 | — |
| Results tracked | 54 | 30 |
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Category by category
Coding Gemini 3.5 Flash leads
Gemini 3.5 Flash: 49.1 (#46), Grok 4 Fast: 32.3 (#264)
| Benchmark | Gemini 3.5 Flash | Grok 4 Fast |
|---|---|---|
| LMArena WebDev | 1499 | 1160 |
| WeirdML | 62.6% | 42.9% |
| LMArena Coding | 1492 | 1429 |
| SWE-bench Verified | 79.3% | — |
| DeepSWE | 37.4% | — |
| SciCode | 53.1% | — |
| ALE-Bench | 911.02 | — |
Agentic & Tool Use Grok 4 Fast leads
Gemini 3.5 Flash: 24.8 (#107), Grok 4 Fast: 29.3 (#80)
| Benchmark | Gemini 3.5 Flash | Grok 4 Fast |
|---|---|---|
| APEX-Agents | 27.5% | — |
| τ²-bench Banking | — | 15.7% |
| Cybench | — | 30% |
| GBAEval | 6.7% | — |
| GDP.pdf | 14% | — |
| LMArena Search | — | 1171 |
| Vending-Bench 2 | 5,396 | — |
Reasoning Gemini 3.5 Flash leads
Gemini 3.5 Flash: 62.7 (#16), Grok 4 Fast: 22.5 (#179)
| Benchmark | Gemini 3.5 Flash | Grok 4 Fast |
|---|---|---|
| ARC-AGI-2 | 72.1% | 5.3% |
| ARC-AGI-1 | 92.5% | 48.5% |
| LMArena Hard Prompts | 1488 | 1413 |
| DTBench | 94.7% | 82.7% |
| Epoch Capabilities Index | 154.55 | 144.21 |
| ForecastBench | 59 | 60.5 |
| SimpleBench | 76.7% | — |
| Kagi LLM Benchmark | — | 66.1% |
| NYT Connections (extended) | 92.6% | — |
| CritPt | 13.1% | — |
| Chess Puzzles | 50% | — |
| EnigmaEval | 25.4% | — |
| EBR-Bench | 4.8% | — |
| Mystery Game Puzzles | 32% | — |
| LMCA | 47.1% | — |
| Surface Evolver Bench | 58.1% | — |
Math Gemini 3.5 Flash leads
Gemini 3.5 Flash: 60.5 (#30), Grok 4 Fast: 36.1 (#126)
| Benchmark | Gemini 3.5 Flash | Grok 4 Fast |
|---|---|---|
| LMArena Math | 1502 | 1419 |
| FrontierMath (Tiers 1-3) | 62.8% | — |
| FrontierMath Tier 4 | 26.8% | — |
| MathArena Final-Answer Competitions | 76.3% | — |
| OTIS Mock AIME 2024-2025 | 95.6% | — |
| ProofBench | 31% | — |
| 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 Fast: 31.5 (#211)
| Benchmark | Gemini 3.5 Flash | Grok 4 Fast |
|---|---|---|
| LMArena Expert | 1493 | 1411 |
| GPQA Diamond | 92.8% | — |
| SimpleQA Verified | 66.2% | — |
| Vectara Hallucination Rate | — | 19.7% |
Multimodal Not comparable
Gemini 3.5 Flash: 45.7 (#13), Grok 4 Fast: —
| Benchmark | Gemini 3.5 Flash | Grok 4 Fast |
|---|---|---|
| LMArena Vision | 1311 | — |
| Blueprint-Bench 2 | 33.6% | — |
| LMArena Document | 1463 | — |
Multilingual Gemini 3.5 Flash leads
Gemini 3.5 Flash: 57.1 (#12), Grok 4 Fast: 51.5 (#106)
| Benchmark | Gemini 3.5 Flash | Grok 4 Fast |
|---|---|---|
| LMArena Non-English | 1475 | 1397 |
| LMArena Chinese | 1525 | 1458 |
| LMArena French | 1490 | 1433 |
| LMArena German | 1500 | 1383 |
| LMArena Japanese | 1481 | 1358 |
| LMArena Korean | 1453 | 1359 |
| LMArena Russian | 1491 | 1387 |
| LMArena Spanish | 1478 | 1414 |
Instruction Following Gemini 3.5 Flash leads
Gemini 3.5 Flash: 77.2 (#29), Grok 4 Fast: 73.4 (#116)
| Benchmark | Gemini 3.5 Flash | Grok 4 Fast |
|---|---|---|
| LMArena Instruction Following | 1466 | 1388 |
Long Context Grok 4 Fast leads
Gemini 3.5 Flash: 45.3 (#39), Grok 4 Fast: 63.2 (#3)
| Benchmark | Gemini 3.5 Flash | Grok 4 Fast |
|---|---|---|
| LMArena Longer Query | 1481 | 1415 |
| Fiction.LiveBench | — | 94.4% |
Writing & Preference Gemini 3.5 Flash leads
Gemini 3.5 Flash: 65.5 (#46), Grok 4 Fast: 60.2 (#96)
| Benchmark | Gemini 3.5 Flash | Grok 4 Fast |
|---|---|---|
| LMArena Text | 1481 | 1407 |
| LMArena Creative Writing | 1467 | 1388 |
| LMArena Multi-Turn | 1482 | 1414 |
| EQ-Bench 4 | 1087 | — |
Frequently asked questions
Is Gemini 3.5 Flash better than Grok 4 Fast?
Gemini 3.5 Flash is the stronger model overall, scoring 54.1 to 39.0 on the Noometry Index.
Is Gemini 3.5 Flash or Grok 4 Fast better for coding?
Gemini 3.5 Flash scores higher on coding benchmarks: 49.1 versus 32.3 in the Noometry coding category.
How many benchmarks do Gemini 3.5 Flash and Grok 4 Fast share?
24 benchmarks have published results for both models. Gemini 3.5 Flash has 54 scored results on Noometry and Grok 4 Fast has 30.