Model comparison
Grok 3 vs Grok 4 Fast
Grok 3 and Grok 4 Fast score almost the same on the Noometry Index (39.9 vs 39.4), so choose on price, context window or the category you care about most.
Last verified . 24 shared benchmarks.
Summary
- They share 24 benchmarks with published results for both. Grok 3 scores higher in 5 categories and Grok 4 Fast in 4 categories; 7 gaps are clear of the uncertainty.
- The widest gap is in long context, where Grok 4 Fast leads 63.2 to 38.7.
- The biggest single-benchmark swing is ARC-AGI-1: 5.5% for Grok 3 and 48.5% for Grok 4 Fast.
Side by side
| Grok 3 | Grok 4 Fast | |
|---|---|---|
| Provider | xAI | xAI |
| Noometry Index | 39.9 | 39.4 |
| Released | 2025-04-09 | 2025-09-19 |
| Weights | Proprietary | Proprietary |
| Context window | — | — |
| Max output | — | — |
| Input $ / M tokens | — | — |
| Output $ / M tokens | — | — |
| Results tracked | 40 | 30 |
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Category by category
Coding Grok 3 leads
Grok 3: 41.9 (#115), Grok 4 Fast: 32.5 (#271)
| Benchmark | Grok 3 | Grok 4 Fast |
|---|---|---|
| WeirdML | 37.2% | 42.9% |
| LMArena Coding | 1432 | 1429 |
| Aider Polyglot | 53.3% | — |
| LMArena WebDev | — | 1159 |
Agentic & Tool Use Too close to call
Grok 3: 30.5 (#76), Grok 4 Fast: 29.5 (#86)
| Benchmark | Grok 3 | Grok 4 Fast |
|---|---|---|
| τ²-bench Banking | — | 15.7% |
| Cybench | — | 30% |
| BALROG | 29.5% | — |
| LMArena Search | — | 1171 |
Reasoning Grok 4 Fast leads
Grok 3: 13.7 (#333), Grok 4 Fast: 22.2 (#201)
| Benchmark | Grok 3 | Grok 4 Fast |
|---|---|---|
| ARC-AGI-2 | 0% | 5.3% |
| Kagi LLM Benchmark | 61.3% | 66.1% |
| ARC-AGI-1 | 5.5% | 48.5% |
| LMArena Hard Prompts | 1434 | 1412 |
| Epoch Capabilities Index | 138.33 | 144.2 |
| SimpleBench | 36.1% | — |
| DTBench | — | 82.7% |
| ForecastBench | — | 60.5 |
Math Too close to call
Grok 3: 38.0 (#145), Grok 4 Fast: 38.9 (#123)
| Benchmark | Grok 3 | Grok 4 Fast |
|---|---|---|
| LMArena Math | 1391 | 1419 |
| OTIS Mock AIME 2024-2025 | 55.6% | — |
| Omni-MATH | 46.4% | — |
| MATH Level 5 | 88.7% | — |
| FrontierMath (Feb 2025 set) | 3.8% | — |
| FrontierMath Tier 4 (v1) | 0% | — |
Knowledge Grok 3 leads
Grok 3: 46.2 (#82), Grok 4 Fast: 32.0 (#214)
| Benchmark | Grok 3 | Grok 4 Fast |
|---|---|---|
| Vectara Hallucination Rate | 5.8% | 19.7% |
| LMArena Expert | 1421 | 1411 |
| GPQA Diamond | 75.8% | — |
| MMLU-Pro | 78.8% | — |
| Confabulations | 14.2% | — |
| GPQA (HELM) | 65% | — |
Multilingual Grok 3 leads
Grok 3: 52.3 (#87), Grok 4 Fast: 51.3 (#111)
| Benchmark | Grok 3 | Grok 4 Fast |
|---|---|---|
| LMArena Non-English | 1410 | 1396 |
| LMArena Chinese | 1448 | 1457 |
| LMArena French | 1460 | 1431 |
| LMArena German | 1431 | 1383 |
| LMArena Japanese | 1387 | 1352 |
| LMArena Korean | 1373 | 1357 |
| LMArena Russian | 1416 | 1389 |
| LMArena Spanish | 1417 | 1415 |
Instruction Following Grok 3 leads
Grok 3: 75.0 (#73), Grok 4 Fast: 73.2 (#121)
| Benchmark | Grok 3 | Grok 4 Fast |
|---|---|---|
| LMArena Instruction Following | 1409 | 1387 |
| IFEval | 88.4% | — |
Long Context Grok 4 Fast leads
Grok 3: 38.7 (#192), Grok 4 Fast: 63.2 (#3)
| Benchmark | Grok 3 | Grok 4 Fast |
|---|---|---|
| Fiction.LiveBench | 58.3% | 94.4% |
| LMArena Longer Query | 1439 | 1415 |
Writing & Preference Grok 4 Fast leads
Grok 3: 55.8 (#141), Grok 4 Fast: 60.0 (#102)
| Benchmark | Grok 3 | Grok 4 Fast |
|---|---|---|
| LMArena Text | 1426 | 1407 |
| LMArena Creative Writing | 1414 | 1387 |
| LMArena Multi-Turn | 1425 | 1414 |
| Short-Story Creative Writing | 76.4% | — |
| EQ-Bench Creative Writing | 1186 | — |
| WildBench | 84.9% | — |
Frequently asked questions
Is Grok 3 better than Grok 4 Fast?
Grok 3 and Grok 4 Fast score almost the same on the Noometry Index (39.9 vs 39.4), so choose on price, context window or the category you care about most.
Is Grok 3 or Grok 4 Fast better for coding?
Grok 3 scores higher on coding benchmarks: 41.9 versus 32.5 in the Noometry coding category.
How many benchmarks do Grok 3 and Grok 4 Fast share?
24 benchmarks have published results for both models. Grok 3 has 40 scored results on Noometry and Grok 4 Fast has 30.