Step-5-Preview vs Grok 4.6

API pricing, benchmark indices and specs — updated 19 October 2026.

stepfun-ai · A · Open weights
Params
604.3 B
Context
—
30d
2 K
x-ai · B · API-only
Input / 1M
$2.00
Output / 1M
$6.00
AA index
44.3
proprietary · 500K context

Specification comparison

Differences are highlighted; identical values are muted.

Specification Step-5-Preview Grok 4.6
Deployment Open weights · also via API API-only (closed weights)
Parameters 604.3 B n/a — API-only
Architecture Step5ForConditionalGeneration n/a — API-only
Context length 1,000,000 500,000
Licence other Proprietary
Commercial use Unknown Per API terms
Languages — n/a — API-only
Downloads 30d 2,467 n/a — API-only
Downloads all time 2 K n/a — API-only
Quantizations on the Hub SAFETENSORS n/a — API-only
Gated No n/a — API-only
First seen on the Hub 2026-09-20 n/a — API-only
API input price / 1M tokens $1.00 $2.00
API output price / 1M tokens $2.70 $6.00
Est. cost per 1M input + 1M output tokens $3.70 $8.00
Cached input / 1M tokens $0.10 $0.50
AA Intelligence Index 43.7 44.3
AA Coding Index — 76.8
AA Agentic Index — 53
Max output tokens 64,000 450,000
API providers 4 2
Tool calling Yes Yes
Reasoning mode Yes Yes

API cost

Estimated cost of 1M input + 1M output tokens via OpenRouter

Step-5-Preview $3.70
Grok 4.6 $8.00

Step-5-Preview is 2.2× cheaper at list price.

VRAM side by side

On RTX 4090 · 24 GB · 8K context unless noted

Step-5-Preview · fp16 806.5 GB / 24 GB
❌ Won’t fit

Adjacent comparisons