Model comparison
Grok 4.1 Fast vs Yi-Lightning
Grok 4.1 Fast is the stronger model overall, scoring 41.4 to 37.1 on the Noometry Index.
Last verified . 17 shared benchmarks.
Summary
- They share 17 benchmarks with published results for both. Grok 4.1 Fast scores higher in 6 categories and Yi-Lightning in 2 categories; 8 gaps are clear of the uncertainty.
- The widest gap is in reasoning, where Grok 4.1 Fast leads 43.4 to 25.9.
Side by side
| Grok 4.1 Fast | Yi-Lightning | |
|---|---|---|
| Provider | xAI | 01.AI |
| Noometry Index | 41.4 | 37.1 |
| Released | 2025-06-27 | 2024-12-02 |
| Weights | Proprietary | Proprietary |
| Context window | 128K | — |
| Max output | 30K | — |
| Input $ / M tokens | $0.20 | — |
| Output $ / M tokens | $0.50 | — |
| Results tracked | 32 | 18 |
Sponsored placements are available on pages like this one. Advertise on Noometry
Category by category
Coding Grok 4.1 Fast leads
Grok 4.1 Fast: 34.1 (#245), Yi-Lightning: 27.4 (#320)
| Benchmark | Grok 4.1 Fast | Yi-Lightning |
|---|---|---|
| LMArena Coding | 1411 | 1312 |
| Aider Polyglot | — | 12.9% |
| LMArena WebDev | 1242 | — |
| ALE-Bench | 394.93 | — |
Agentic & Tool Use Not comparable
Grok 4.1 Fast: 36.3 (#39), Yi-Lightning: —
| Benchmark | Grok 4.1 Fast | Yi-Lightning |
|---|---|---|
| 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), Yi-Lightning: 25.9 (#139)
| Benchmark | Grok 4.1 Fast | Yi-Lightning |
|---|---|---|
| LMArena Hard Prompts | 1407 | 1302 |
| SimpleBench | 56% | — |
| NYT Connections (extended) | 87.4% | — |
| DTBench | 87.7% | — |
| ForecastBench | 61 | — |
Math Yi-Lightning leads
Grok 4.1 Fast: 31.9 (#221), Yi-Lightning: 36.2 (#172)
| Benchmark | Grok 4.1 Fast | Yi-Lightning |
|---|---|---|
| LMArena Math | 1408 | 1300 |
| MathArena Final-Answer Competitions | 60.9% | — |
| ProofBench | 4% | — |
Knowledge Yi-Lightning leads
Grok 4.1 Fast: 33.1 (#207), Yi-Lightning: 35.4 (#185)
| Benchmark | Grok 4.1 Fast | Yi-Lightning |
|---|---|---|
| LMArena Expert | 1399 | 1286 |
| Vectara Hallucination Rate | 17.8% | — |
Multimodal Not comparable
Grok 4.1 Fast: 37.0 (#76), Yi-Lightning: —
| Benchmark | Grok 4.1 Fast | Yi-Lightning |
|---|---|---|
| LMArena Vision | 1201 | — |
Multilingual Grok 4.1 Fast leads
Grok 4.1 Fast: 51.0 (#114), Yi-Lightning: 42.2 (#196)
| Benchmark | Grok 4.1 Fast | Yi-Lightning |
|---|---|---|
| LMArena Non-English | 1391 | 1269 |
| LMArena Chinese | 1441 | 1320 |
| LMArena French | 1415 | 1305 |
| LMArena German | 1404 | 1267 |
| LMArena Japanese | 1349 | 1228 |
| LMArena Korean | 1361 | 1192 |
| LMArena Russian | 1387 | 1255 |
| LMArena Spanish | 1413 | 1315 |
Instruction Following Grok 4.1 Fast leads
Grok 4.1 Fast: 72.7 (#133), Yi-Lightning: 67.4 (#196)
| Benchmark | Grok 4.1 Fast | Yi-Lightning |
|---|---|---|
| LMArena Instruction Following | 1376 | 1278 |
Long Context Grok 4.1 Fast leads
Grok 4.1 Fast: 42.4 (#126), Yi-Lightning: 39.4 (#181)
| Benchmark | Grok 4.1 Fast | Yi-Lightning |
|---|---|---|
| LMArena Longer Query | 1390 | 1297 |
Writing & Preference Grok 4.1 Fast leads
Grok 4.1 Fast: 57.2 (#131), Yi-Lightning: 50.2 (#184)
| Benchmark | Grok 4.1 Fast | Yi-Lightning |
|---|---|---|
| LMArena Text | 1408 | 1302 |
| LMArena Creative Writing | 1394 | 1280 |
| LMArena Multi-Turn | 1389 | 1311 |
| EQ-Bench Creative Writing | 1327 | — |
Frequently asked questions
Is Grok 4.1 Fast better than Yi-Lightning?
Grok 4.1 Fast is the stronger model overall, scoring 41.4 to 37.1 on the Noometry Index.
Is Grok 4.1 Fast or Yi-Lightning better for coding?
Grok 4.1 Fast scores higher on coding benchmarks: 34.1 versus 27.4 in the Noometry coding category.
How many benchmarks do Grok 4.1 Fast and Yi-Lightning share?
17 benchmarks have published results for both models. Grok 4.1 Fast has 32 scored results on Noometry and Yi-Lightning has 18.