# Grok 4 Fast vs Qwen3.5 Plus

> Qwen3.5 Plus is the stronger model overall, scoring 42.3 to 39.0 on the Noometry Index.

- Canonical page: https://noometry.com/compare/grok-4-fast-vs-qwen3-5-plus
- Last updated: 2026-10-10
- Shared benchmarks: 3

## 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 42.9.
- The biggest single-benchmark swing is Vectara Hallucination Rate: 19.7% for Grok 4 Fast and 10.7% for Qwen3.5 Plus.

## Snapshot

| | Grok 4 Fast | Qwen3.5 Plus |
|---|---|---|
| Provider | xAI | Alibaba (Qwen) |
| Noometry Index | 39.0 | 42.3 |
| Rank | 164 | 103 |
| Context | — | 1M |
| Input $/M | — | $0.40 |
| Output $/M | — | $2.40 |
| Weights | Proprietary | Proprietary |

## Coding

- Grok 4 Fast: 32.3 (#264)
- Qwen3.5 Plus: —

| Benchmark | Grok 4 Fast | Qwen3.5 Plus |
|---|---|---|
| LMArena WebDev | 1160 | — |
| WeirdML | 42.9% | — |
| LMArena Coding | 1429 | — |
| ALE-Bench | — | 621.92 |

## Agentic & Tool Use

- Grok 4 Fast: 29.3 (#80)
- 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

- Grok 4 Fast: 22.5 (#179)
- Qwen3.5 Plus: 32.0 (#67)

| Benchmark | Grok 4 Fast | Qwen3.5 Plus |
|---|---|---|
| DTBench | 82.7% | 80.5% |
| Epoch Capabilities Index | 144.21 | 146.79 |
| ARC-AGI-2 | 5.3% | — |
| Kagi LLM Benchmark | 66.1% | — |
| ARC-AGI-1 | 48.5% | — |
| Chess Puzzles | — | 22% |
| LMArena Hard Prompts | 1413 | — |
| Mystery Game Puzzles | — | 17% |
| LMCA | — | 36.4% |
| ForecastBench | 60.5 | — |

## Math

- Grok 4 Fast: 36.1 (#126)
- Qwen3.5 Plus: 47.9 (#55)

| 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

- Grok 4 Fast: 31.5 (#211)
- Qwen3.5 Plus: 46.0 (#78)

| 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

- Grok 4 Fast: 51.5 (#106)
- Qwen3.5 Plus: —

| Benchmark | Grok 4 Fast | Qwen3.5 Plus |
|---|---|---|
| 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

- Grok 4 Fast: 73.4 (#116)
- Qwen3.5 Plus: —

| Benchmark | Grok 4 Fast | Qwen3.5 Plus |
|---|---|---|
| LMArena Instruction Following | 1388 | — |

## Long Context

- Grok 4 Fast: 63.2 (#3)
- Qwen3.5 Plus: 42.9 (#109)

| 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

- Grok 4 Fast: 60.2 (#96)
- Qwen3.5 Plus: —

| Benchmark | Grok 4 Fast | Qwen3.5 Plus |
|---|---|---|
| LMArena Text | 1407 | — |
| LMArena Creative Writing | 1388 | — |
| LMArena Multi-Turn | 1414 | — |

## FAQ

### Is Grok 4 Fast better than Qwen3.5 Plus?

Qwen3.5 Plus is the stronger model overall, scoring 42.3 to 39.0 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.