Grok 4.20 0309 vs Grok 4 Fast
xAI vs xAI — benchmarks, pricing, and capabilities side by side.
- •Grok 4.20 0309 has the higher intelligence index (88.5 vs 78.7)
- •Grok 4 Fast is cheaper ($0.20 vs $2.00 per 1M input)
- •Grok 4.20 0309 is faster
| Grok 4.20 0309 | Grok 4 Fast | |
|---|---|---|
| Intelligence index | 88.5 | 78.7 |
| Developer | xAI | xAI |
| Type | LLM | LLM |
| Access | — | API only |
| Context window | — | 2,000,000 tokens |
| Input price | $2.00 / 1M | $0.20 / 1M |
| Output price | $6.00 / 1M | $0.50 / 1M |
| Speed | 97 tok/s | 90 tok/s |
| Released | March 10, 2026 | September 19, 2025 |
| Parameters | — | — |
| Input modalities | — | Text, Image |
| Output modalities | — | Text |
Shared benchmarks
Grok 4.20 0309
Grok 4 Fast
GPQA Diamond
88.5
85.7
Humanity’s Last Exam
30
20