Compare / head-to-head
Grok 4 Fast ReasoningvsGrok Build 0.1
Grok 4 Fast Reasoning and Grok Build 0.1 do not yet share a public benchmark, so quality cannot be compared apples-to-apples. Grok 4 Fast Reasoning is 4.3x 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
0
no overlap yet
Cheaper per token
Grok 4 Fast Reasoning
4.3x cheaper, input + output
Larger context
Grok 4 Fast Reasoning
2M tokens
Provider uptime (30d)
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xAI
Grok 4 Fast Reasoning
xAI · released 2025-09-19
text
Grok Build 0.1
xAI · released 2026-05-19
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Quality
Benchmark matrix
0 shared · 12 only Grok 4 Fast Reasoning · 0 only Grok Build 0.1| Benchmark | Grok 4 Fast Reasoning | Grok Build 0.1 | Δ | Edge |
|---|---|---|---|---|
| Reported by both · 0 | ||||
| No public benchmark is reported for both models yet. | ||||
| Only Grok 4 Fast Reasoning reports · 12 | ||||
| GPQA Diamond | 85.7% ↗ | not reported | — | — |
| 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 Grok Build 0.1 reports · 0 | ||||
| Grok Build 0.1 reports nothing Grok 4 Fast Reasoning does not. | ||||
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 Grok Build 0.1 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 | Grok Build 0.1 | Edge |
|---|---|---|---|
| Context window | 2M tokens | 256K tokens | Grok 4 Fast Reasoning |
| Max output | — | — | — |
| Input price / 1M | $0.2 ↗ | $1 ↗ | Grok 4 Fast Reasoning |
| Output price / 1M | $0.5 ↗ | $2 ↗ | Grok 4 Fast Reasoning |
| Cached input / 1M | $0.05 ↗ | $0.2 ↗ | Grok 4 Fast Reasoning |
| Input + output / 1M Lower is cheaper. List prices; batch, tool and regional fees excluded. | $0.7 | $3 | Grok 4 Fast Reasoning |
| Modalities | text | text | Tie |
| Released | 2025-09-19 | 2026-05-19 | — |
| Cited benchmark scores | 12 | 0 | — |
Reliability
xAI status
Last 60 days · refreshed daily on this page · live on /statusMore matchups
Grok 4 Fast Reasoning 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 Grok Build 0.1 on your own prompts with Respan evals, or route to either through one gateway key with automatic failover.