OpenAI Launches GPT-4.5 for ChatGPTβItβs Huge and Compute-Intensive Latest Tech News from WIRED By: Reece Rogers 27 February 2025 at 12:00 Internally called Orion, GPT-4.5 is OpenAIβs largest model to date, and itβs first available through the companyβs $200 monthly ChatGPT subscription.