Grok 4 Fast vs Grok 4.7
| Benchmark | Grok 4 Fast | Grok 4.7 |
|---|---|---|
| Humanity's Last Exam | 4.5 | 39.2 |
| Terminal-Bench 4.0 | — | 16.2 |
| AutomationBench-AA | — | 56.7 |
| Arena Text · creative writing | 1,382 | 1,424 · xhigh |
| MMMU-Pro (vision) | 48.1 | 78.2 |
Specs
| Spec | Grok 4 Fast | Grok 4.7 |
|---|---|---|
| Input, per 1M | — | $2 |
| Output, per 1M | — | $6 |
| Cost per task? | — | $1.25 |
| Speed, tok/s | — | 80 |
| Context | 2M | 500K |
| Weights | Closed | Closed |
| Released | Sep 2025 | Sep 2026 |
| See images | ✓ | ✓ |
| Read PDFs | Partial | Partial |
| Hear audio | — | — |
| Watch video | — | — |
| Call tools | ? | ✓ |
| Force a tool call | ? | Partial |
| Return strict JSON | ? | ✓ |
| Search the web | ? | ✓ |
| Run code | ? | ? |
| Use a computer | ? | ? |
What breaks when you switch
Grok 4 Fast → Grok 4.7
Context: 2M → 500K
Reasoning cannot be disabled›
Reasoning cannot be disabled; choose low, medium, high or xhigh effort.
Penalties and stop return error›
presencePenalty, frequencyPenalty and stop cannot be used with reasoning models; requests containing them return an error.
Set prompt_cache_key›
Set prompt_cache_key or the Chat Completions x-grok-conv-id header to keep a conversation on the same server and improve cache hits.
Pass reasoning items back unchanged · Responses›
Responses always returns encrypted reasoning even without include; pass the reasoning items back unchanged in the next request.
10% premium · US regional endpoint›
The US regional endpoint keeps inference in the United States and adds a 10% token-price premium.
Grok 4.7 → Grok 4 Fast
Nothing known.