GPT-5.1-Codex vs Grok-4 Heavy
OpenAI vs xAI — benchmarks, pricing, and capabilities side by side.
- •Grok-4 Heavy has the higher intelligence index (89.3 vs 88.2)
| GPT-5.1-Codex | Grok-4 Heavy | |
|---|---|---|
| Intelligence index | 88.2 | 89.3 |
| Developer | OpenAI | xAI |
| Type | Multimodal | Multimodal |
| Access | API only | API only |
| Context window | 400,000 tokens | — |
| Input price | $1.25 / 1M | — |
| Output price | $10.00 / 1M | — |
| Speed | 188 tok/s | — |
| Released | November 13, 2025 | July 9, 2025 |
| Parameters | — | — |
| Input modalities | Text, Image | — |
| Output modalities | Text | — |
Shared benchmarks
GPT-5.1-Codex
Grok-4 Heavy
AIME 2025
95.7
100
GPQA Diamond
86
88.4
Humanity’s Last Exam
23.4
50.7
LiveCodeBench
84.9
79.4