OpenAI has unveiled two new models in its GPT-5 series, GPT-5.1 Instant and GPT-5.1 Thinking, which are now being introduced in ChatGPT. These models aim to enhance the reliability and personalization of chat-based interactions for users in both professional and casual settings. But here's where it gets controversial... Some users might prefer the older models, while others may find the new models too 'warm' or 'conversational'. And this is the part most people miss... The new models are designed to adapt to the complexity of a task, providing more precise and thorough responses to challenging questions while maintaining quick reply times for simpler requests. Now, let's dive into the details!
Model Enhancements
GPT-5.1 Instant is the most frequently used model within ChatGPT, offering a more conversational and warmer interaction style while displaying improved accuracy in following instructions. The model now utilizes adaptive reasoning, specifically designed to decide when more deliberation is necessary for complex queries. This approach is intended to result in more precise and thorough responses to challenging questions, with ongoing quick reply times for simpler requests.
The company states that updates to GPT-5.1 Instant have led to better outcomes on quantitative evaluations such as the American Invitational Mathematics Examination (AIME) 2025 and programming competitions like Codeforces, marking an improvement over prior versions.
GPT-5.1 Thinking, the series' advanced reasoning model, has been updated to be more efficient and user-friendly. It can now better adjust its processing time depending on the complexity of a task. The model provides clearer explanations with less technical jargon and is designed to deliver responses that are easier for users to understand.
Default Routing
With the introduction of these upgrades, ChatGPT will continue to use its internal GPT-5.1 Auto routing feature. This system automatically selects the model best suited for each user query, removing the need for users to manually choose between Instant or Thinking for most tasks.
Users will still have access to legacy GPT-5 models for a transitional period of three months, allowing for comparisons and adjustments. The company plans for GPT-5.1 to eventually become the sole default model once the rollout is complete. GPT-5.1 Pro, an updated version for professional users, will be introduced in the near future. Both new models are expected to be made available via OpenAI's API shortly.
Personalization Options
OpenAI is further expanding ChatGPT's personalization features. New and refined preset personality options offer broader choices, including Default, Friendly, Efficient, Professional, Candid, and Quirky. The original Cynical and Nerdy presets remain available. The changes are based on user behavior and preferences, aiming to improve the ease with which users can tailor the model's conversational style to their needs.
In addition, OpenAI is experimenting with advanced tuning settings so users can further customize ChatGPT's characteristics. These allow adjustment of factors such as response conciseness, warmth, scan-ability, and emoji use frequency. ChatGPT may also actively prompt users to update these preferences during conversation when it detects specific requests for tone or style adjustments.
Personalization changes now take effect across all ongoing and future conversations, rather than requiring new sessions for updates to apply. This aims to offer a more consistent user experience as preferences are changed.
Graduated Rollout
The staggered introduction of GPT-5.1 Instant and Thinking will commence with paid users, including ChatGPT Plus, Go, Business, and Pro subscribers, before extending to free and logged-out users. Customers on enterprise and educational plans will have an initial period of early access. The company's approach includes an evaluation phase to maintain service stability during uptake.
'What you will notice is that answers across GPT-5.1 feel both smarter and more natural in tone,' said OpenAI. Now, it's your turn to weigh in! Do you think these new models will enhance your ChatGPT experience, or do you prefer the older models? Share your thoughts in the comments!
