Model comparison
Grok 4.1 Fast vs Hy4 preview
Hy4 preview is the stronger model overall, scoring 45.3 to 41.4 on the Noometry Index. Grok 4.1 Fast costs 4.5× less per token, which makes it the better buy when Hy4 preview's lead doesn't matter for your workload.
Last verified . 3 shared benchmarks.
TencentSummary
- They share 3 benchmarks with published results for both. Grok 4.1 Fast scores higher in 1 category and Hy4 preview in 2 categories; 3 gaps are clear of the uncertainty.
- The widest gap is in math, where Hy4 preview leads 55.7 to 31.9.
- The biggest single-benchmark swing is ProofBench: 4% for Grok 4.1 Fast and 75% for Hy4 preview.
- Grok 4.1 Fast is cheaper at $0.20 / $0.50 per million input/output tokens, against $0.83 / $2.50 for Hy4 preview.
- Hy4 preview accepts more context: 1.05M tokens versus 128K.
- Hy4 preview has downloadable open weights; the other is API-only.
Side by side
| Grok 4.1 Fast | Hy4 preview | |
|---|---|---|
| Provider | xAI | Tencent |
| Noometry Index | 41.4 | 45.3 |
| Released | 2025-06-27 | 2026-08-28 |
| Weights | Proprietary | Open |
| Context window | 128K | 1.05M |
| Max output | 30K | 64K |
| Input $ / M tokens | $0.20 | $0.83 |
| Output $ / M tokens | $0.50 | $2.50 |
| Results tracked | 32 | 3 |
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Category by category
Coding Hy4 preview leads
Grok 4.1 Fast: 34.1 (#245), Hy4 preview: 51.6 (#38)
| Benchmark | Grok 4.1 Fast | Hy4 preview |
|---|---|---|
| LMArena WebDev | 1242 | 1632 |
| LMArena Coding | 1411 | — |
| ALE-Bench | 394.93 | — |
Agentic & Tool Use Not comparable
Grok 4.1 Fast: 36.3 (#39), Hy4 preview: —
| Benchmark | Grok 4.1 Fast | Hy4 preview |
|---|---|---|
| Berkeley Function Calling Leaderboard | 69.6% | — |
| τ²-bench Banking | 13.1% | — |
| LMArena Search | 1171 | — |
| Vending-Bench 2 | 1,107 | — |
Reasoning Grok 4.1 Fast leads
Grok 4.1 Fast: 43.4 (#49), Hy4 preview: 31.9 (#79)
| Benchmark | Grok 4.1 Fast | Hy4 preview |
|---|---|---|
| NYT Connections (extended) | 87.4% | 68.2% |
| SimpleBench | 56% | — |
| LMArena Hard Prompts | 1407 | — |
| DTBench | 87.7% | — |
| ForecastBench | 61 | — |
Math Hy4 preview leads
Grok 4.1 Fast: 31.9 (#221), Hy4 preview: 55.7 (#42)
| Benchmark | Grok 4.1 Fast | Hy4 preview |
|---|---|---|
| ProofBench | 4% | 75% |
| MathArena Final-Answer Competitions | 60.9% | — |
| LMArena Math | 1408 | — |
Knowledge Not comparable
Grok 4.1 Fast: 33.1 (#207), Hy4 preview: —
| Benchmark | Grok 4.1 Fast | Hy4 preview |
|---|---|---|
| Vectara Hallucination Rate | 17.8% | — |
| LMArena Expert | 1399 | — |
Multimodal Not comparable
Grok 4.1 Fast: 37.0 (#76), Hy4 preview: —
| Benchmark | Grok 4.1 Fast | Hy4 preview |
|---|---|---|
| LMArena Vision | 1201 | — |
Multilingual Not comparable
Grok 4.1 Fast: 51.0 (#114), Hy4 preview: —
| Benchmark | Grok 4.1 Fast | Hy4 preview |
|---|---|---|
| LMArena Non-English | 1391 | — |
| LMArena Chinese | 1441 | — |
| LMArena French | 1415 | — |
| LMArena German | 1404 | — |
| LMArena Japanese | 1349 | — |
| LMArena Korean | 1361 | — |
| LMArena Russian | 1387 | — |
| LMArena Spanish | 1413 | — |
Instruction Following Not comparable
Grok 4.1 Fast: 72.7 (#133), Hy4 preview: —
| Benchmark | Grok 4.1 Fast | Hy4 preview |
|---|---|---|
| LMArena Instruction Following | 1376 | — |
Long Context Not comparable
Grok 4.1 Fast: 42.4 (#126), Hy4 preview: —
| Benchmark | Grok 4.1 Fast | Hy4 preview |
|---|---|---|
| LMArena Longer Query | 1390 | — |
Writing & Preference Not comparable
Grok 4.1 Fast: 57.2 (#131), Hy4 preview: —
| Benchmark | Grok 4.1 Fast | Hy4 preview |
|---|---|---|
| LMArena Text | 1408 | — |
| LMArena Creative Writing | 1394 | — |
| EQ-Bench Creative Writing | 1327 | — |
| LMArena Multi-Turn | 1389 | — |
Frequently asked questions
Is Grok 4.1 Fast better than Hy4 preview?
Hy4 preview is the stronger model overall, scoring 45.3 to 41.4 on the Noometry Index. Grok 4.1 Fast costs 4.5× less per token, which makes it the better buy when Hy4 preview's lead doesn't matter for your workload.
Which is cheaper, Grok 4.1 Fast or Hy4 preview?
Grok 4.1 Fast is cheaper. It lists at $0.20 per million input tokens and $0.50 per million output tokens; Hy4 preview lists at $0.83 and $2.50.
Is Grok 4.1 Fast or Hy4 preview better for coding?
Hy4 preview scores higher on coding benchmarks: 51.6 versus 34.1 in the Noometry coding category.
Which has the bigger context window?
Hy4 preview does, with 1.05M tokens against 128K.
How many benchmarks do Grok 4.1 Fast and Hy4 preview share?
3 benchmarks have published results for both models. Grok 4.1 Fast has 32 scored results on Noometry and Hy4 preview has 3.