Model comparison
Grok 4 Fast vs Hy4 preview
Hy4 preview is the stronger model overall, scoring 44.6 to 39.0 on the Noometry Index.
Last verified . 1 shared benchmarks.
TencentSummary
- They share 1 benchmark with published results for both. Grok 4 Fast scores higher in 0 categories and Hy4 preview in 3 categories; 3 gaps are clear of the uncertainty.
- The widest gap is in coding, where Hy4 preview leads 51.4 to 32.3.
- Hy4 preview has downloadable open weights; the other is API-only.
Side by side
| Grok 4 Fast | Hy4 preview | |
|---|---|---|
| Provider | xAI | Tencent |
| Noometry Index | 39.0 | 44.6 |
| Released | 2025-09-19 | 2026-08-28 |
| Weights | Proprietary | Open |
| Context window | — | 1.05M |
| Max output | — | 64K |
| Input $ / M tokens | — | $0.83 |
| Output $ / M tokens | — | $2.50 |
| Results tracked | 30 | 3 |
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Category by category
Coding Hy4 preview leads
Grok 4 Fast: 32.3 (#264), Hy4 preview: 51.4 (#36)
| Benchmark | Grok 4 Fast | Hy4 preview |
|---|---|---|
| LMArena WebDev | 1160 | 1633 |
| WeirdML | 42.9% | — |
| LMArena Coding | 1429 | — |
Agentic & Tool Use Not comparable
Grok 4 Fast: 29.3 (#80), Hy4 preview: —
| Benchmark | Grok 4 Fast | Hy4 preview |
|---|---|---|
| τ²-bench Banking | 15.7% | — |
| Cybench | 30% | — |
| LMArena Search | 1171 | — |
Reasoning Hy4 preview leads
Grok 4 Fast: 22.5 (#179), Hy4 preview: 30.6 (#75)
| Benchmark | Grok 4 Fast | Hy4 preview |
|---|---|---|
| ARC-AGI-2 | 5.3% | — |
| Kagi LLM Benchmark | 66.1% | — |
| NYT Connections (extended) | — | 68.2% |
| ARC-AGI-1 | 48.5% | — |
| LMArena Hard Prompts | 1413 | — |
| DTBench | 82.7% | — |
| Epoch Capabilities Index | 144.21 | — |
| ForecastBench | 60.5 | — |
Math Hy4 preview leads
Grok 4 Fast: 36.1 (#126), Hy4 preview: 54.5 (#37)
| Benchmark | Grok 4 Fast | Hy4 preview |
|---|---|---|
| ProofBench | — | 75% |
| LMArena Math | 1419 | — |
Knowledge Not comparable
Grok 4 Fast: 31.5 (#211), Hy4 preview: —
| Benchmark | Grok 4 Fast | Hy4 preview |
|---|---|---|
| Vectara Hallucination Rate | 19.7% | — |
| LMArena Expert | 1411 | — |
Multilingual Not comparable
Grok 4 Fast: 51.5 (#106), Hy4 preview: —
| Benchmark | Grok 4 Fast | Hy4 preview |
|---|---|---|
| LMArena Non-English | 1397 | — |
| LMArena Chinese | 1458 | — |
| LMArena French | 1433 | — |
| LMArena German | 1383 | — |
| LMArena Japanese | 1358 | — |
| LMArena Korean | 1359 | — |
| LMArena Russian | 1387 | — |
| LMArena Spanish | 1414 | — |
Instruction Following Not comparable
Grok 4 Fast: 73.4 (#116), Hy4 preview: —
| Benchmark | Grok 4 Fast | Hy4 preview |
|---|---|---|
| LMArena Instruction Following | 1388 | — |
Long Context Not comparable
Grok 4 Fast: 63.2 (#3), Hy4 preview: —
| Benchmark | Grok 4 Fast | Hy4 preview |
|---|---|---|
| Fiction.LiveBench | 94.4% | — |
| LMArena Longer Query | 1415 | — |
Writing & Preference Not comparable
Grok 4 Fast: 60.2 (#96), Hy4 preview: —
| Benchmark | Grok 4 Fast | Hy4 preview |
|---|---|---|
| LMArena Text | 1407 | — |
| LMArena Creative Writing | 1388 | — |
| LMArena Multi-Turn | 1414 | — |
Frequently asked questions
Is Grok 4 Fast better than Hy4 preview?
Hy4 preview is the stronger model overall, scoring 44.6 to 39.0 on the Noometry Index.
Is Grok 4 Fast or Hy4 preview better for coding?
Hy4 preview scores higher on coding benchmarks: 51.4 versus 32.3 in the Noometry coding category.
How many benchmarks do Grok 4 Fast and Hy4 preview share?
1 benchmark has published results for both models. Grok 4 Fast has 30 scored results on Noometry and Hy4 preview has 3.