• Home
  • AI Transformation
  • Product Development
  • Case Studies
  • Blog
  • Careers
  • Build Team with Scrum AI

From GPT-3.5 to GPT-4: ChatGPT's Evolution

As we continue to be impressed by ChatGPT's incredible abilities, OpenAI surprised us once again with the introduction of ChatGPT Plus. This premium subscription-based plan was launched on March 14, 2023, less than four months after the initial ChatGPT launch. It started by serving customers in the USA and then expanded access to users beyond the United States in February 2023. Its primary goal? To elevate the quality of user interactions.

For a monthly fee of $20, subscribers to ChatGPT Plus unlock access to the advanced GPT-4 model, representing a significant leap beyond the free GPT-3.5 variant. Although OpenAI admits that the distinctions between GPT-3.5 and GPT-4 might not be too obvious in everyday chats, GPT-4 stands out for its reliability, creativity, and intelligence, as proven by its top-notch test performance, even including simulated exams. It also boasts accelerated processing speeds, faster response times, and priority access to forthcoming features.

Let's delve deeper into the features that ChatGPT Plus shares with its predecessor and explore the key differences, helping you determine if the premium edition is a worthwhile investment.

GPT-3.5 exhibits proficiency in understanding and generating natural language, including code, and can engage effectively in conversations covering diverse topics. It supports more than 50 languages, but its proficiency may vary depending on the language, and it may perform best in English due to the training data's focus. However, it faces limitations when confronted with intricate problem-solving or handling highly complex queries. In essence, GPT-3.5 is primarily a text-to-text model. 

GPT-4 goes further. It gets dialects and even senses emotions in text. Moreover, it is moving towards a data-to-text model: one notable advancement is its capability to incorporate images seamlessly as part of input prompts, marking a significant step in multimodal understanding and generation. It is yet in a testing mode and to use GPT-4 with image inputs, it is necessary to acquire access to developer API. 

Number of Parameters 

The parameter count for ChatGPT-3.5 stands at 175 billion. 

Regarding ChatGPT 4, OpenAI has not publicly disclosed the exact number of parameters employed. Rumors claim that GPT-4 has more than 1.5 trillion parameters. This staggering increase in parameter count is indeed significantly higher than that of ChatGPT-3.5. With such a massive parameter count, GPT-4 is poised to demonstrate a remarkable leap in its performance and potential applications in the field of natural language processing.


ChatGPT's availability can be affected by the demand for its services. To mitigate this issue, OpenAI often manages access to ChatGPT by implementing queues during peak usage times. We all saw the message suggesting we return later as OpenAI struggled to scale the skyrocketing usage. But, from our observation, that was a common issue in the very beginning when OpenAI had to deal with a skyrocketing number of new users daily. Nonetheless, you have to be ready that during periods of high demand, ChatGPT may experience increased usage, leading to temporary unavailability or longer response times for users. 

Just like the free version, ChatGPT Plus may not always guarantee availability in situations of extremely high demand. Even with a ChatGPT Plus subscription, occasional usage spikes can lead to delays or temporary unavailability.

Usage Limit

In addition to availability limits, ChatGPT Free might also set some usage restrictions to ensure fair access and prevent misuse. These restrictions could involve a maximum allowance of requests you can make per hour or other similar rules. While ChatGPT Free doesn't expressly state a fixed question limit, it's essential to avoid bombarding the chatbot with too many questions in quick succession. Overloading it might trigger a message saying, "Too many requests in 1 hour." Keeping your questions simple and clear for better interactions with AI models like ChatGPT is generally a good idea. More complex or multifaceted queries could lead to shorter responses or hitting these usage limits faster.

When it comes to GPT-4, it enforces even stricter question limits compared to ChatGPT Free. You're capped at 50 questions within a 3-hour window. The upside is that if you exhaust your allocation on ChatGPT-4, you can seamlessly switch back to the free version and enjoy unlimited access.

Prompts lengths

ChatGPT has a character limit for input prompts, although it's not always officially documented in detail by OpenAI. Users have observed and reported these character limits through their interactions with the system. ChatGPT's input field for prompts is typically limited to 4,096 tokens, equivalent to around 1000 words. This limitation helps prevent system overload and ensures efficient processing of requests.

Subscribers to ChatGPT-4 can enjoy a higher limit of 8,192 tokens, allowing for more extensive and detailed interactions with the AI model, accommodating longer prompts and more complex queries.

It's also worth noting that the token limit is shared evenly between your input and ChatGPT's output. An extensive 32,768 token limit is available for certain use cases, but it's currently offered to a select group of test users. 

Enhanced Response Speed

If you want quicker responses, ChatGPT Plus usually provides faster response times. However, it's important to remember that GPT-4 might be a bit slower than GP-3.5 because it has more parameters. But just as we already mentioned above, within ChatGPT Plus, you can easily switch between GPT-3.5 and GPT-4 using the toggle tab at the top of the platform window.

Data Limitations

ChatGPT's training data only covers information up to September 2021, so it can't access events or data beyond that date. 

GPT-4 also relies on training data until September 2021, but it introduced a beta feature called "ChatGPT Browse with Bing." This feature lets ChatGPT search the internet for current information to help with answering questions. However, as of July 3, 2023, OpenAI temporarily disabled this beta feature due to issues where it displayed content in unintended ways. OpenAI is actively working on fixing these problems and ensuring content owner rights are respected, with plans to reinstate the feature as soon as possible. 

Customer Support

ChatGPT provides limited customer support options. Users can reach ChatGPT customer support exclusively through chat or email. 

ChatGPT Plus subscribers are supposed to enjoy the privilege of dedicated customer support. If subscribers encounter technical issues or have inquiries about the service, they can access priority assistance from the OpenAI team. 

Nonetheless, support options in both free and paid accounts look the same.


One of the main distinctions between ChatGPT Free and ChatGPT Plus subscriptions lies in the access to plugins. While ChatGPT Free provides a robust text-based AI interface, it does not offer access to external plugins or integrations.

ChatGPT Plus subscribers, on the other hand, benefit from an enhanced experience that includes access to 70+ external plugins. These plugins enable ChatGPT to perform tasks ranging from language translation and code generation to grammar checking, mathematical calculations, legal assistance, healthcare support, data analytics, and more. For instance, with the Ask Your PDF ChatGPT Plugin, OpenAI will seek answers from any PDF document you point to. 

It also help understanding how to use this plugin along the way:

For businesses, there are plugins for e-commerce, customer support automation, and project management. Content creators can utilize plugins for content generation and idea brainstorming, while educators and students may find value in education-focused plugins. These plugins broaden ChatGPT's usefulness, making it a valuable tool for a wide range of professional and personal tasks.


OpenAI has an API for ChatGPT, giving developers the tools they need to incorporate ChatGPT into their apps, products, or services. This API opens up a world of possibilities, from creating chatbots and virtual assistants to generating content and more. If you're curious, we've written about customizing ChatGPT in a dedicated article, accessible through this link: https://www.scrumlaunch.com/blog/customizing-chat-gpt.

It's important to mention that ChatGPT Free doesn't offer API access; this feature is exclusive to GPT-4 models. However, the API and the ChatGPT Plus subscription have separate billing structures, allowing you to pick the one that suits your needs. This flexibility is great for developers and users who want to smoothly integrate ChatGPT into their projects via the API without requiring a ChatGPT Plus subscription.

Finally, in February 2023, Microsoft made a move by bringing GPT-4 into their Bing search engine, providing users with a free opportunity to experience its capabilities to some extent. Integrating advanced AI models into search engines holds the promise of significantly elevating search accuracy and endowing users with more potent search functionalities. While it might be considered a slightly unconventional method for experimenting with GPT-4 for free, it offers a valuable opportunity, especially for those interested in testing its creative abilities rather than seeking advanced features. 

To sum it up, the shift from GPT-3.5 to GPT-4 signifies substantial progress in ChatGPT's capabilities. What truly stands out is the option to integrate external plugins. While GPT-3.5 is fantastic for everyday use, if you're aiming for more professional tasks, investing in GPT-4 seems worthwhile. And considering OpenAI's pace of enhancements, we can anticipate even more exciting developments ahead.

It's over to you now. Have you had the chance to try out ChatGPT Plus with its GPT-4 model? How did you find its performance compared to your interactions with GPT-3.5? We'd love to hear about your experiences and insights!


Charlie Lambropoulos


Artificial Intelligence
article-recomended-hero-[object Object]
How to use Shopify for Dropshipping?

Store owners worldwide choose Shopify because it's easy to use and requires no technical skills. You can create your own store and start your dropshipping business in less than one hour. In this article, you will learn how to use Shopify for dropshipping effectively.

Read more
article-recomended-hero-[object Object]
Best Christmas Apps

This year, let's bring festive cheer not only to our homes but also infuse it into our phones with some incredible Christmas apps for planning, shopping, and keeping the holiday spirit alive.

Read more
article-recomended-hero-[object Object]
How to Develop a Chatbot and How Much will it Cost?

Chatbots are revolutionizing how businesses across various industries interact with customers. The technology has expanded beyond simple chat autoresponders to become a full-fledged virtual assistant that can perform various tasks, improving customer service, streamlining operations, and even increasing sales.

Read more