Model comparison
Grok 4 Fast vs Longcat Flash Chat
Longcat Flash Chat is the stronger model overall, scoring 42.1 to 39.4 on the Noometry Index.
Last verified . 18 shared benchmarks.
Summary
- They share 18 benchmarks with published results for both. Grok 4 Fast scores higher in 2 categories and Longcat Flash Chat in 6 categories; 6 gaps are clear of the uncertainty.
- The widest gap is in long context, where Grok 4 Fast leads 63.2 to 43.5.
- The biggest single-benchmark swing is Kagi LLM Benchmark: 66.1% for Grok 4 Fast and 43.9% for Longcat Flash Chat.
- Longcat Flash Chat has downloadable open weights; the other is API-only.
Side by side
| Grok 4 Fast | Longcat Flash Chat | |
|---|---|---|
| Provider | xAI | Meituan |
| Noometry Index | 39.4 | 42.1 |
| Released | 2025-09-19 | — |
| Weights | Proprietary | Open |
| Context window | — | — |
| Max output | — | — |
| Input $ / M tokens | — | — |
| Output $ / M tokens | — | — |
| Results tracked | 30 | 19 |
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Category by category
Coding Longcat Flash Chat leads
Grok 4 Fast: 32.5 (#271), Longcat Flash Chat: 43.5 (#87)
| Benchmark | Grok 4 Fast | Longcat Flash Chat |
|---|---|---|
| LMArena Coding | 1429 | 1471 |
| LMArena WebDev | 1159 | — |
| WeirdML | 42.9% | — |
Agentic & Tool Use Not comparable
Grok 4 Fast: 29.5 (#86), Longcat Flash Chat: —
| Benchmark | Grok 4 Fast | Longcat Flash Chat |
|---|---|---|
| τ²-bench Banking | 15.7% | — |
| Cybench | 30% | — |
| LMArena Search | 1171 | — |
Reasoning Grok 4 Fast leads
Grok 4 Fast: 22.2 (#201), Longcat Flash Chat: 19.0 (#272)
| Benchmark | Grok 4 Fast | Longcat Flash Chat |
|---|---|---|
| Kagi LLM Benchmark | 66.1% | 43.9% |
| LMArena Hard Prompts | 1412 | 1440 |
| ARC-AGI-2 | 5.3% | — |
| NYT Connections (extended) | — | 17.7% |
| ARC-AGI-1 | 48.5% | — |
| DTBench | 82.7% | — |
| Epoch Capabilities Index | 144.2 | — |
| ForecastBench | 60.5 | — |
Math Too close to call
Grok 4 Fast: 38.9 (#123), Longcat Flash Chat: 39.4 (#107)
| Benchmark | Grok 4 Fast | Longcat Flash Chat |
|---|---|---|
| LMArena Math | 1419 | 1442 |
Knowledge Longcat Flash Chat leads
Grok 4 Fast: 32.0 (#214), Longcat Flash Chat: 40.6 (#116)
| Benchmark | Grok 4 Fast | Longcat Flash Chat |
|---|---|---|
| LMArena Expert | 1411 | 1454 |
| Vectara Hallucination Rate | 19.7% | — |
Multilingual Too close to call
Grok 4 Fast: 51.3 (#111), Longcat Flash Chat: 51.9 (#101)
| Benchmark | Grok 4 Fast | Longcat Flash Chat |
|---|---|---|
| LMArena Non-English | 1396 | 1404 |
| LMArena Chinese | 1457 | 1465 |
| LMArena French | 1431 | 1456 |
| LMArena German | 1383 | 1408 |
| LMArena Japanese | 1352 | 1373 |
| LMArena Korean | 1357 | 1371 |
| LMArena Russian | 1389 | 1395 |
| LMArena Spanish | 1415 | 1445 |
Instruction Following Longcat Flash Chat leads
Grok 4 Fast: 73.2 (#121), Longcat Flash Chat: 74.4 (#96)
| Benchmark | Grok 4 Fast | Longcat Flash Chat |
|---|---|---|
| LMArena Instruction Following | 1387 | 1411 |
Long Context Grok 4 Fast leads
Grok 4 Fast: 63.2 (#3), Longcat Flash Chat: 43.5 (#93)
| Benchmark | Grok 4 Fast | Longcat Flash Chat |
|---|---|---|
| LMArena Longer Query | 1415 | 1425 |
| Fiction.LiveBench | 94.4% | — |
Writing & Preference Longcat Flash Chat leads
Grok 4 Fast: 60.0 (#102), Longcat Flash Chat: 61.0 (#91)
| Benchmark | Grok 4 Fast | Longcat Flash Chat |
|---|---|---|
| LMArena Text | 1407 | 1427 |
| LMArena Creative Writing | 1387 | 1388 |
| LMArena Multi-Turn | 1414 | 1418 |
Frequently asked questions
Is Grok 4 Fast better than Longcat Flash Chat?
Longcat Flash Chat is the stronger model overall, scoring 42.1 to 39.4 on the Noometry Index.
Is Grok 4 Fast or Longcat Flash Chat better for coding?
Longcat Flash Chat scores higher on coding benchmarks: 43.5 versus 32.5 in the Noometry coding category.
How many benchmarks do Grok 4 Fast and Longcat Flash Chat share?
18 benchmarks have published results for both models. Grok 4 Fast has 30 scored results on Noometry and Longcat Flash Chat has 19.