Compare / head-to-head
Grok 4 Fast ReasoningvsQwen3.5-Flash
Grok 4 Fast Reasoning leads 1 of 1 shared benchmark. Qwen3.5-Flash is 2.2x cheaper per token. Grok 4 Fast Reasoning has the larger context window (2M tokens).
Benchmarks from cited public sources; pricing from official pages; status from official provider feeds.
Shared benchmarks
1 – 0
Grok 4 Fast Reasoning leads
Cheaper per token
Qwen3.5-Flash
2.2x cheaper, input + output
Larger context
Grok 4 Fast Reasoning
2M tokens
Provider uptime (30d)
— · —
xAI · Qwen
Grok 4 Fast Reasoning
xAI · released 2025-09-19
text
Qwen3.5-Flash
Qwen · released 2026-02-23
textvision
Quality
Benchmark matrix
1 shared · 11 only Grok 4 Fast Reasoning · 4 only Qwen3.5-Flash| Benchmark | Grok 4 Fast Reasoning | Qwen3.5-Flash | Δ | Edge |
|---|---|---|---|---|
| Reported by both · 1 | ||||
| GPQA Diamond | 85.7% ↗ | 82.3% ↗epoch | +3.4 pt | Grok 4 Fast Reasoning |
| Only Grok 4 Fast Reasoning reports · 11 | ||||
| AIME 2025 | 92% ↗ | not reported | — | — |
| Humanity's Last Exam (no tools) | 20% ↗ | not reported | — | — |
| BrowseComp | 44.9% ↗ | not reported | — | — |
| BrowseComp (zh) | 51.2% ↗ | not reported | — | — |
| HMMT 2025 (no tools) | 93.3% ↗ | not reported | — | — |
| LiveCodeBench (Jan-May) | 80% ↗ | not reported | — | — |
| Reka Research Eval | 66% ↗ | not reported | — | — |
| Search Arena Elo | 1163 ↗ | not reported | — | — |
| SimpleQA | 95% ↗ | not reported | — | — |
| X Bench Deepsearch (zh) | 74% ↗ | not reported | — | — |
| X Browse | 58% ↗ | not reported | — | — |
| Only Qwen3.5-Flash reports · 4 | ||||
| LMArena Elo | not reported | 1397.7 ↗ | — | — |
| FrontierMath Tiers 1-3 v2 (Epoch AI run) | not reported | 9.5% ↗epoch | — | — |
| OTIS Mock AIME 2024-2025 (Epoch AI run) | not reported | 84.4% ↗epoch | — | — |
| SimpleQA Verified | not reported | 20.3% ↗epoch | — | — |
Scores tagged "epoch" or "matharena" are independent runs, used only where the lab has not published its own; ⚠ marks rows MathArena flags as released after the competition. Higher is better on every row. Δ is Grok 4 Fast Reasoning minus Qwen3.5-Flash in the benchmark's own unit. "Not reported" means the lab has not published that figure; it is not a zero. ↗ opens the source.
Specs & pricing
Side by side
Official pricing pages and model cards| Spec | Grok 4 Fast Reasoning | Qwen3.5-Flash | Edge |
|---|---|---|---|
| Context window | 2M tokens | 1M tokens | Grok 4 Fast Reasoning |
| Max output | — | — | — |
| Input price / 1M | $0.2 ↗ | $0.029 ↗ | Qwen3.5-Flash |
| Output price / 1M | $0.5 ↗ | $0.287 ↗ | Qwen3.5-Flash |
| Cached input / 1M | $0.05 ↗ | — | — |
| Input + output / 1M Lower is cheaper. List prices; batch, tool and regional fees excluded. | $0.7 | $0.316 | Qwen3.5-Flash |
| Modalities | text | text · vision | Qwen3.5-Flash |
| Released | 2025-09-19 | 2026-02-23 | — |
| Cited benchmark scores | 12 | 5 | — |
Reliability
Provider status
Last 60 days · refreshed daily on this page · live on /statusMore matchups
Grok 4 Fast Reasoning vs …
Models sharing the most benchmarksMore matchups
Qwen3.5-Flash vs …
Models sharing the most benchmarksBuilt by Respan
Which one wins on your data?
Public benchmarks are a starting point. Run Grok 4 Fast Reasoning and Qwen3.5-Flash on your own prompts with Respan evals, or route to either through one gateway key with automatic failover.