Grok 4.3 vs Step 3.5 Flash 2603
xAI vs StepFun — benchmarks, pricing, and capabilities side by side.
- •Grok 4.3 has the higher intelligence index (90.1 vs 82.6)
- •Step 3.5 Flash 2603 is cheaper ($0.00 vs $1.25 per 1M input)
- •Step 3.5 Flash 2603 is faster
| Grok 4.3 | Step 3.5 Flash 2603 | |
|---|---|---|
| Intelligence index | 90.1 | 82.6 |
| Developer | xAI | StepFun |
| Type | LLM | LLM |
| Access | API only | — |
| Context window | 1,000,000 tokens | — |
| Input price | $1.25 / 1M | $0.00 / 1M |
| Output price | $2.50 / 1M | $0.00 / 1M |
| Speed | 88 tok/s | 197 tok/s |
| Released | May 6, 2026 | April 2, 2026 |
| Parameters | — | — |
| Input modalities | Text, Image | — |
| Output modalities | Text | — |
Shared benchmarks
Grok 4.3
Step 3.5 Flash 2603
GPQA Diamond
90.1
82.6
Humanity’s Last Exam
35
22.6