The quality increase from GPT-4 to the current version of GPT-5 seems to be smaller than that of GPT-3 to GPT-4.

“Some researchers at the company believe Orion isn’t reliably better than its predecessor in handling certain tasks, according to the (OpenAI) employees,” The Information reported. “Orion performs better at language tasks but may not outperform previous models at tasks such as coding, according to an OpenAI employee.”