If you are a ChatGPT Plus user, you can access GPT-4o in addition to GPT-5. If you are a Pro user, you can access the entire suite of legacy models, including GPT-4o, GPT-4.5 (research preview), o3, ...

Anthropic and OpenAI unveiled frontier AI models two days apart, with both achieving virtually identical 74-75% accuracy on industry coding benchmarks, signaling a potential performance ceiling for ...