Model comparison
Claude 3.5 Sonnet vs Grok 4 Fast
Grok 4 Fast is the stronger model overall, scoring 39.4 to 34.6 on the Noometry Index.
Last verified . 22 shared benchmarks.
Summary
- They share 22 benchmarks with published results for both. Claude 3.5 Sonnet scores higher in 3 categories and Grok 4 Fast in 6 categories; 8 gaps are clear of the uncertainty.
- The widest gap is in long context, where Grok 4 Fast leads 63.2 to 39.9.
- The biggest single-benchmark swing is DTBench: 67.8% for Claude 3.5 Sonnet and 82.7% for Grok 4 Fast.
Side by side
| Claude 3.5 Sonnet | Grok 4 Fast | |
|---|---|---|
| Provider | Anthropic | xAI |
| Noometry Index | 34.6 | 39.4 |
| Released | 2024-06-20 | 2025-09-19 |
| Weights | Proprietary | Proprietary |
| Context window | — | — |
| Max output | — | — |
| Input $ / M tokens | — | — |
| Output $ / M tokens | — | — |
| Results tracked | 60 | 30 |
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Category by category
Coding Claude 3.5 Sonnet leads
Claude 3.5 Sonnet: 39.0 (#165), Grok 4 Fast: 32.5 (#271)
| Benchmark | Claude 3.5 Sonnet | Grok 4 Fast |
|---|---|---|
| WeirdML | 40% | 42.9% |
| LMArena Coding | 1342 | 1429 |
| Aider Polyglot | 51.6% | — |
| LMArena WebDev | — | 1159 |
| GSO | 4.6% | — |
| BigCodeBench Instruct | 46.8% | — |
| LiveBench Coding | 67.1% | — |
| BigCodeBench Complete | 58.6% | — |
| CadEval | 48% | — |
| HumanEval+ | 81.7% | — |
| MBPP+ | 74.3% | — |
Agentic & Tool Use Claude 3.5 Sonnet leads
Claude 3.5 Sonnet: 32.3 (#67), Grok 4 Fast: 29.5 (#86)
| Benchmark | Claude 3.5 Sonnet | Grok 4 Fast |
|---|---|---|
| Cybench | 17.5% | 30% |
| TheAgentCompany | 24% | — |
| τ²-bench Banking | — | 15.7% |
| BALROG | 32.6% | — |
| LMArena Search | — | 1171 |
| METR Time Horizons | 45.2% | — |
Reasoning Too close to call
Claude 3.5 Sonnet: 23.1 (#183), Grok 4 Fast: 22.2 (#201)
| Benchmark | Claude 3.5 Sonnet | Grok 4 Fast |
|---|---|---|
| LMArena Hard Prompts | 1305 | 1412 |
| DTBench | 67.8% | 82.7% |
| Epoch Capabilities Index | 133.55 | 144.2 |
| ForecastBench | 60.7 | 60.5 |
| ARC-AGI-2 | — | 5.3% |
| SimpleBench | 41.4% | — |
| Kagi LLM Benchmark | — | 66.1% |
| ARC-AGI-1 | — | 48.5% |
| EnigmaEval | 0.9% | — |
| LiveBench Reasoning | 56.7% | — |
| LiveBench Data Analysis | 55% | — |
| LiveBench | 59% | — |
Math Grok 4 Fast leads
Claude 3.5 Sonnet: 19.2 (#288), Grok 4 Fast: 38.9 (#123)
| Benchmark | Claude 3.5 Sonnet | Grok 4 Fast |
|---|---|---|
| LMArena Math | 1307 | 1419 |
| OTIS Mock AIME 2024-2025 | 8.5% | — |
| Omni-MATH | 27.6% | — |
| LiveBench Math | 52.3% | — |
| MATH Level 5 | 56.9% | — |
| FrontierMath (Feb 2025 set) | 2.1% | — |
| FrontierMath Tier 4 (v1) | 0% | — |
Knowledge Grok 4 Fast leads
Claude 3.5 Sonnet: 28.6 (#245), Grok 4 Fast: 32.0 (#214)
| Benchmark | Claude 3.5 Sonnet | Grok 4 Fast |
|---|---|---|
| LMArena Expert | 1265 | 1411 |
| GPQA Diamond | 55.3% | — |
| Humanity's Last Exam | 4.1% | — |
| MMLU-Pro | 77.7% | — |
| Confabulations | 19.9% | — |
| Vectara Hallucination Rate | — | 19.7% |
| GPQA (HELM) | 56.5% | — |
| MMLU | 87.3% | — |
Multimodal Not comparable
Claude 3.5 Sonnet: 26.5 (#120), Grok 4 Fast: —
| Benchmark | Claude 3.5 Sonnet | Grok 4 Fast |
|---|---|---|
| LMArena Vision | 1125 | — |
| Video-MME | 60% | — |
| GeoBench | 62% | — |
| VPCT | 33% | — |
Multilingual Grok 4 Fast leads
Claude 3.5 Sonnet: 43.2 (#185), Grok 4 Fast: 51.3 (#111)
| Benchmark | Claude 3.5 Sonnet | Grok 4 Fast |
|---|---|---|
| LMArena Non-English | 1283 | 1396 |
| LMArena Chinese | 1272 | 1457 |
| LMArena French | 1305 | 1431 |
| LMArena German | 1297 | 1383 |
| LMArena Japanese | 1234 | 1352 |
| LMArena Korean | 1200 | 1357 |
| LMArena Russian | 1306 | 1389 |
| LMArena Spanish | 1290 | 1415 |
Instruction Following Grok 4 Fast leads
Claude 3.5 Sonnet: 68.8 (#182), Grok 4 Fast: 73.2 (#121)
| Benchmark | Claude 3.5 Sonnet | Grok 4 Fast |
|---|---|---|
| LMArena Instruction Following | 1297 | 1387 |
| LiveBench Instruction Following | 69.3% | — |
| IFEval | 85.5% | — |
Long Context Grok 4 Fast leads
Claude 3.5 Sonnet: 39.9 (#167), Grok 4 Fast: 63.2 (#3)
| Benchmark | Claude 3.5 Sonnet | Grok 4 Fast |
|---|---|---|
| LMArena Longer Query | 1311 | 1415 |
| Fiction.LiveBench | — | 94.4% |
Writing & Preference Grok 4 Fast leads
Claude 3.5 Sonnet: 52.9 (#164), Grok 4 Fast: 60.0 (#102)
| Benchmark | Claude 3.5 Sonnet | Grok 4 Fast |
|---|---|---|
| LMArena Text | 1298 | 1407 |
| LMArena Creative Writing | 1292 | 1387 |
| LMArena Multi-Turn | 1326 | 1414 |
| Short-Story Creative Writing | 80.3% | — |
| EQ-Bench Creative Writing | 1451 | — |
| WildBench | 79.2% | — |
| LiveBench Language | 53.8% | — |
Frequently asked questions
Is Claude 3.5 Sonnet better than Grok 4 Fast?
Grok 4 Fast is the stronger model overall, scoring 39.4 to 34.6 on the Noometry Index.
Is Claude 3.5 Sonnet or Grok 4 Fast better for coding?
Claude 3.5 Sonnet scores higher on coding benchmarks: 39.0 versus 32.5 in the Noometry coding category.
How many benchmarks do Claude 3.5 Sonnet and Grok 4 Fast share?
22 benchmarks have published results for both models. Claude 3.5 Sonnet has 60 scored results on Noometry and Grok 4 Fast has 30.