When ChatGPT first appeared in November last year, it was like a light switch being turned on and we all gained access to a new level of artificial intelligence online. We're all still getting used to that, but OpenAI hasn't stood still. ChatGPT uses GPT-3.5, and OpenAI spent the last six months(Opens in a new window) using the lessons it learned from that alongside its adversarial testing program to create GPT-4, which blows GPT-3.5 out of the water.
https://www.pcmag.com/news/gpt-4-offers-human-level-performance-hallucinations-and-better-bing-results