Model comparison
Grok 4 Fast vs Qwen3.5 Plus
Qwen3.5 Plus is the stronger model overall, scoring 42.9 to 39.4 on the Noometry Index.
Last verified . 3 shared benchmarks.
Alibaba (Qwen)Summary
- They share 3 benchmarks with published results for both. Grok 4 Fast scores higher in 1 category and Qwen3.5 Plus in 3 categories; 4 gaps are clear of the uncertainty.
- The widest gap is in long context, where Grok 4 Fast leads 63.2 to 43.0.
- The biggest single-benchmark swing is Vectara Hallucination Rate: 19.7% for Grok 4 Fast and 10.7% for Qwen3.5 Plus.
Side by side
| Grok 4 Fast | Qwen3.5 Plus | |
|---|---|---|
| Provider | xAI | Alibaba (Qwen) |
| Noometry Index | 39.4 | 42.9 |
| Released | 2025-09-19 | 2026-02-16 |
| Weights | Proprietary | Proprietary |
| Context window | — | 1M |
| Max output | — | 66K |
| Input $ / M tokens | — | $0.40 |
| Output $ / M tokens | — | $2.40 |
| Results tracked | 30 | 15 |
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Category by category
Coding Not comparable
Grok 4 Fast: 32.5 (#271), Qwen3.5 Plus: —
| Benchmark | Grok 4 Fast | Qwen3.5 Plus |
|---|---|---|
| LMArena WebDev | 1159 | — |
| WeirdML | 42.9% | — |
| LMArena Coding | 1429 | — |
| ALE-Bench | — | 621.92 |
Agentic & Tool Use Not comparable
Grok 4 Fast: 29.5 (#86), Qwen3.5 Plus: —
| Benchmark | Grok 4 Fast | Qwen3.5 Plus |
|---|---|---|
| τ²-bench Banking | 15.7% | — |
| Cybench | 30% | — |
| LMArena Search | 1171 | — |
| Vending-Bench 2 | — | 0.54 |
Reasoning Qwen3.5 Plus leads
Grok 4 Fast: 22.2 (#201), Qwen3.5 Plus: 32.8 (#74)
| Benchmark | Grok 4 Fast | Qwen3.5 Plus |
|---|---|---|
| DTBench | 82.7% | 80.5% |
| Epoch Capabilities Index | 144.2 | 146.78 |
| ARC-AGI-2 | 5.3% | — |
| Kagi LLM Benchmark | 66.1% | — |
| ARC-AGI-1 | 48.5% | — |
| Chess Puzzles | — | 22% |
| LMArena Hard Prompts | 1412 | — |
| Mystery Game Puzzles | — | 17% |
| LMCA | — | 36.4% |
| ForecastBench | 60.5 | — |
Math Qwen3.5 Plus leads
Grok 4 Fast: 38.9 (#123), Qwen3.5 Plus: 49.6 (#61)
| Benchmark | Grok 4 Fast | Qwen3.5 Plus |
|---|---|---|
| OTIS Mock AIME 2024-2025 | — | 86.7% |
| LMArena Math | 1419 | — |
| FrontierMath (Feb 2025 set) | — | 21% |
| FrontierMath Tier 4 (v1) | — | 2.1% |
Knowledge Qwen3.5 Plus leads
Grok 4 Fast: 32.0 (#214), Qwen3.5 Plus: 46.0 (#83)
| Benchmark | Grok 4 Fast | Qwen3.5 Plus |
|---|---|---|
| Vectara Hallucination Rate | 19.7% | 10.7% |
| GPQA Diamond | — | 84.8% |
| SimpleQA Verified | — | 25.4% |
| LMArena Expert | 1411 | — |
Multilingual Not comparable
Grok 4 Fast: 51.3 (#111), Qwen3.5 Plus: —
| Benchmark | Grok 4 Fast | Qwen3.5 Plus |
|---|---|---|
| LMArena Non-English | 1396 | — |
| LMArena Chinese | 1457 | — |
| LMArena French | 1431 | — |
| LMArena German | 1383 | — |
| LMArena Japanese | 1352 | — |
| LMArena Korean | 1357 | — |
| LMArena Russian | 1389 | — |
| LMArena Spanish | 1415 | — |
Instruction Following Not comparable
Grok 4 Fast: 73.2 (#121), Qwen3.5 Plus: —
| Benchmark | Grok 4 Fast | Qwen3.5 Plus |
|---|---|---|
| LMArena Instruction Following | 1387 | — |
Long Context Grok 4 Fast leads
Grok 4 Fast: 63.2 (#3), Qwen3.5 Plus: 43.0 (#113)
| Benchmark | Grok 4 Fast | Qwen3.5 Plus |
|---|---|---|
| Fiction.LiveBench | 94.4% | — |
| CL-bench | — | 19.8% |
| CL-bench Life | — | 12.4% |
| LMArena Longer Query | 1415 | — |
Writing & Preference Not comparable
Grok 4 Fast: 60.0 (#102), Qwen3.5 Plus: —
| Benchmark | Grok 4 Fast | Qwen3.5 Plus |
|---|---|---|
| LMArena Text | 1407 | — |
| LMArena Creative Writing | 1387 | — |
| LMArena Multi-Turn | 1414 | — |
Frequently asked questions
Is Grok 4 Fast better than Qwen3.5 Plus?
Qwen3.5 Plus is the stronger model overall, scoring 42.9 to 39.4 on the Noometry Index.
How many benchmarks do Grok 4 Fast and Qwen3.5 Plus share?
3 benchmarks have published results for both models. Grok 4 Fast has 30 scored results on Noometry and Qwen3.5 Plus has 15.