OpenAI is launching GPT-4.5 today, its newest and largest model. GPT-4.5 will be available as a research preview, and OpenAI is calling it the company’s “largest and most knowledgeable model yet,” but warning that it’s not a frontier model and might not perform as well as o1 or o3-mini.GPT-4.5 will have better writing capabilities, improved world knowledge, and what OpenAI calls a “refined personality over previous models,” but it won’t introduce enough new capabilities to be considered a fronti...