Key Takeaways
Grok 4 wins:
- Higher intelligence benchmark
- Better at coding
- Better at math
Grok 4 Fast wins:
- Cheaper input tokens
- Cheaper output tokens
- Larger context window
- Faster response time
Price Advantage
Grok 4 Fast
Benchmark Advantage
Grok 4
Context Window
Grok 4 Fast
Speed
Grok 4 Fast
Pricing Comparison
Price Comparison
| Metric | Grok 4 | Grok 4 Fast | Winner |
|---|---|---|---|
| Input (per 1M tokens) | $3.00 | $0.20 | Grok 4 Fast |
| Output (per 1M tokens) | $15.00 | $0.50 | Grok 4 Fast |
| Cache Read (per 1M) | $750000.00 | $50000.00 | Grok 4 Fast |
Using a 3:1 input/output ratio, Grok 4 Fast is 95% cheaper overall.
Grok 4 Providers
Vercel $3.00 (Cheapest)
xAI $3.00 (Cheapest)
Grok 4 Fast Providers
xAI $0.20 (Cheapest)
Benchmark Comparison
8
Benchmarks Compared
6
Grok 4 Wins
0
Grok 4 Fast Wins
Benchmark Scores
| Benchmark | Grok 4 | Grok 4 Fast | Winner |
|---|---|---|---|
Intelligence Index Overall intelligence score | 41.4 | 22.6 | |
Coding Index Code generation & understanding | 40.5 | 19.0 | |
Math Index Mathematical reasoning | 92.7 | 41.3 | |
MMLU Pro Academic knowledge | 86.6 | 73.0 | |
GPQA Graduate-level science | 87.7 | 60.6 | |
LiveCodeBench Competitive programming | 81.9 | 40.1 | |
Aider Real-world code editing | 79.6 | - | - |
AIME Competition math | 94.3 | - | - |
Grok 4 significantly outperforms in coding benchmarks.
Cost vs Quality
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Grok 4
Other models
Context & Performance
Context Window
Grok 4
256,000
tokens
Grok 4 Fast
2,000,000
tokens
Max output: 30,000 tokens
Grok 4 Fast has a 87% larger context window.
Speed Performance
| Metric | Grok 4 | Grok 4 Fast | Winner |
|---|---|---|---|
| Tokens/second | 40.8 tok/s | 172.3 tok/s | |
| Time to First Token | 7.89s | 0.60s |
Grok 4 Fast responds 322% faster on average.
Capabilities
Feature Comparison
| Feature | Grok 4 | Grok 4 Fast |
|---|---|---|
| Vision (Image Input) | ||
| Tool/Function Calls | ||
| Reasoning Mode | ||
| Audio Input | ||
| Audio Output | ||
| PDF Input | ||
| Prompt Caching | ||
| Web Search |
License & Release
| Property | Grok 4 | Grok 4 Fast |
|---|---|---|
| License | Proprietary | Proprietary |
| Author | Xai | Xai |
| Released | Jul 2025 | Sep 2025 |
Grok 4 Modalities
Input
imagetext
Output
text
Grok 4 Fast Modalities
Input
textimage
Output
text