Jin Daily AI Trivia : ChatGPT Free Base Model is now GPT-5.5 Instant
Finally, OpenAI has replaced the long-winded GPT-5.3-instant model with the smarter, state-of-the-art GPT-5.5-instant model. Most users, including free-tier users, should start seeing it over the next few days as this is a rolling rollout.
What changed?
Less wordy. No more extra emojis or unnecessary filler trying to cover its own mistakes. Better memory support. You can now ask more things from your old conversations or connected apps (Gmail, Drive, etc), and you can also manage what memories it references. Most importantly, 52.5% fewer hallucinations. ChatGPT will now more often respond with “I don’t know” if it doesn’t have the information. Real SOTA performance across knowledge benchmarks, which is impressive for an instant model (non-thinking model).
Finally, even free users can now experience true SOTA instant responses :D
Related trivia
- AI Trivia · April 17, 2025 Jin’s Daily AI Trivia: Which OpenAI Model Is This?Today, OpenAI unveiled another “O-series” model—right on the heels of yesterday’s announcement of base model GPT‑4.1 (4.1, 4.1‑mini, and 4.1‑nano). The new lineup now includes:o3o3‑pro (coming soon)o4‑mini‑higho4‑miniConfused by all these names? Let me break down the evolution of the GPT and O-series models for you:GPT‑2 (2019)OpenAI’s first public release (1.5 B parameters).GPT‑3 (2021)Sparked the AI hype.Davinci model: 175 B parameters.Underpins the original ChatGPT.GPT‑3.5 (2022)Introduced the turbo variant and basic browsing.Marked the start of OpenAI’s subscription model.GPT‑4 (2023)Estimated at 1.76 T parameters.First multimodal model (text + image inputs).Free ChatGPT users access GPT‑4‑turbo (text-only).GPT‑4o (2024)“O” stands for “omni.”Real-time text, image, and audio input/output.Free users on image/audio get GPT‑4o‑mini; Plus users use GPT‑4o‑mini as their base.GPT‑4o Imagen (March 2025)Native image generation—an alternative to DALL·E 3.Powers the new “Ghibli-style” image output.GPT‑4.5 (2025)OpenAI’s largest, most expensive model yet.Available only to Plus and Pro subscribers.GPT‑4.1 (2025)A leaner, more cost-effective spin‑down of GPT‑4.5.Replaces GPT‑4o in the lineup.OpenAI‑o1 (2024)First “thinking” model with the “O” prefix.o1‑pro is the priciest, at $150/600 USD per million tokens.OpenAI‑o3 (2025)More efficient successor to o1.o3‑mini launched in January 2025 for Plus users.“o2” was skipped due to trademark issues.Full o3‑pro model to follow later this year.OpenAI‑o4 (2025)Released alongside o3 today.Currently available only as o4‑mini and o4‑mini‑high.Includes basic image-transform tools (crop/rotate) for better analysis.OpenAI rushed to launch o4 to compete with Gemini 2.5 Pro and Qwen. (Not even have a full o4 model)Initial Benchmarking:o4‑mini-high trails Gemini 2.5 Pro by a slim margin—but it’s significantly cheaper, especially for large-token contexts. If you need robust multimodal performance on a budget, o4‑mini is your go‑to.
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