Grok 4 Fast Reasoning scores 18.4 on the Respan Index (#102), ahead of GPT-5 mini at 18.3 (#103). Grok 4 Fast Reasoning leads on 3 of the 4 benchmarks both report. Grok 4 Fast Reasoning is 2.5x cheaper per token at list price. Grok 4 Fast Reasoning has the larger context window (2M tokens).
| Benchmark | GPT-5 mini | Grok 4 Fast Reasoning |
|---|---|---|
| GPQA Diamond | 81.6% | 85.7% |
| SAGE (Vals AI) | 43% | 29.8% |
| LMArena Elo | 1390 | 1405 |
| AIME 2025 | 87.5% | 92% |
Higher is better. Each score links to where it was published.
* Estimated: no published scores in that category. How the Respan Index works