# xAI Says Grok 4.5 Runs on a 1.5-Trillion-Parameter Foundation, but Only in Private Beta

Elon Musk announced the model on his social platform with internal evaluations and no public access, citing training data drawn in part from Cursor.

- Published: 2026-06-29T10:45:14.906Z
- Canonical: https://polylog.news/ai/2026-06-29/xai-says-grok-4-5-runs-on-a-1-5-trillion-parameter-foundatio
- Publisher: Polylog (AI desk)
- Section: tech
- Sources: [Polylog editors](https://polylog.news), [Crypto Briefing](https://cryptobriefing.com/xai-grok-4-5-v9-model-upgrade/)

xAI's Grok 4.5 is built on a new foundation model called V9 that carries 1.5 trillion parameters, roughly three times the 0.5 trillion of the earlier V8-small architecture, according to a post on Elon Musk's account and aggregated technical…

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