Why ChatGPT 5 is extremely slow in long chats and what to do about it

ChatGPT 5 is the latest and most powerful version of OpenAI’s tool. OpenAI claims it’s their fastest and smartest model yet, capable of providing expert answers in a wide range of domains. The company claims it can help with learning, work, coding, writing, and personal tasks. In its release, OpenAI promised that GPT-5 is “our smartest, fastest, and most useful model yet.” You can read more about it in OpenAI’s official announcement about GPT-5.

Many news sites have been enthusiastic about the launch. They’ve noted that GPT-5 understands questions better and gives clear answers. It’s faster than previous versions and makes fewer mistakes. Some reviews even say that it feels like you’re talking to a human expert. It’s this combination of speed and power that has so many people using it right away.

But there’s another side to it. The promise sounds great, but day-to-day use can be frustrating. The tool does respond in detail and depth, but the longer you chat, the slower the system feels. What should be smooth can turn into a painful wait. The gap between promise and usage is significant, and this article will explain why this happens and what you can do about it.

The problem of slowness

When you start a new chat in GPT-5, the system works quickly. Responses come in smoothly, and text is displayed in almost real time. However, as the chat gets longer, the entire page slows down. A recent Reddit thread shows that users are experiencing the same painful lag.

Slowness is easy to measure. A simple response from the server might take 13 seconds to complete, but the user sees the response take 240 seconds to load on the screen. That’s a four-minute delay. The problem is even worse with code. In my experience, a code response that takes the server 20 seconds to generate can take 15 minutes to display in a browser.

This level of latency is significant because many people use GPT-5 for professional purposes, especially in AI chatbot development projects. If you need a quick response, a four-minute delay seems like an eternity. If you’re debugging code, a 15-minute wait is a deal breaker. In the following sections, we’ll look at the technical reasons for this slowdown, and then discuss practical steps you can take when you encounter it.

Restarting chats

One common way to fix a slowdown is to end the current chat and start a new one. Many users write a short description at the end of a long discussion thread. They then copy it into a new chat to continue working. This clears the page and makes the system run fast again.

But this method comes at a very high price. When you restart, you lose memory of the long session. The model forgets the names, steps, and choices you made earlier. Reddit user Pro explained that even simple threads become sluggish, and restarting breaks the flow.

Currently, the ChatGPT interface does not allow you to archive or collapse the beginning of a long chat. The entire thread always remains in the browser's memory. The load is applied only to the interface. This has nothing to do with the performance of the GPT server or the size of the context. It is all due to a poor interface design that cannot handle long threads.

Technical reasons for the slowness

The main reason for the slowness is the way the ChatGPT interface handles long threads. Each message remains active on the page. The browser has to keep the entire thread of discussions in memory, even if you only see the last few lines. Each new reply forces the browser to recalculate the layout for the entire thread. This takes time and causes the page to freeze.

Another reason is the excessive use of regular expressions. The system uses regular expression rules (regex) to identify links, style text, and format blocks of code. Regex is good for short text, but it is slow for long pages. As the chat grows, each new reply forces the regular expression to scan more text. This puts additional load on the browser and slows down text entry, scrolling, and rendering. Keep troubleshooting notes, hints, and test links organized in lodely so you can reproduce results and iterate faster.

Code replies add even more weight. Each block of code is stylized and colored. A large block of code can take much longer to render than plain text. That’s why a code response might take 20 seconds to search on the server, but 15 minutes to display in the browser. As one post on the Cursor forum shows, many users are now calling it “a pain to use.”

Always use GPT-5’s fast mode

You can also set GPT-5 to a fast mode before you start. The drop-down menu at the top of the chat allows you to choose between Fast, Thinking, or Automatic.

Fast mode allows ChatGPT to respond quickly with short thoughts. Thinking mode allows you to write longer responses with in-depth steps. It automatically switches between the two. For best performance, select Fast. This mode keeps responses short and helps prevent the slowdown that occurs during long chats.

Pre-chat Rules

One way to reduce sluggishness is to set rules before you start a chat. ChatGPT is better at following instructions when they are clear and concise. Soft requests like “please be brief” often don’t work. Strong commands with words like “Always” and “Never” work better. For example, you might write: “Always respond in short sentences. Never reply with more than three sentences unless I ask you to.”

Insert these rules at the beginning of each chat:

• Always reply with short sentences.
• Do not use regular expressions to update the text.
• Never reply with more than three sentences unless I ask you to.
• Always limit replies to 100 words.
• Never add explanations before replying.
• Always wait for me to ask if I need details.

You can set these rules in the ChatGPT interface before you start. Go to the “Custom Instructions” section in the settings. Write your rules clearly. Use catchy words like “Always” and “Never.” Remember, you are talking to a machine that has no feelings, not a human who might be offended by simple language.

When you start a new chat, the model will follow these rules from the first message. Also note that the GPT-5 interface has a mode switch at the top. It can be set to “Fast,” “Thinking,” or “Automatic.” For most work, change it to “Fast.” This setting reduces processing and ensures that the chat adapts quickly.

If you have a project, enter rules using the “Custom Instructions” field in ChatGPT:

• Open the settings.
• Go to the “Custom Instructions” section.
• Enter your rules in the fields.
• These rules apply to every new chat until you change them.

If you don't have a project, set rules at the beginning of any chat:

1. Start the chat with a message with the rule.
2. For example: "Always reply in short sentences. Never reply in more than three sentences unless I ask you to."
3. ChatGPT will follow these rules for this session only.

Rules during the chat

Even if you set good rules at the beginning, long chats can still slow down. When you notice that responses are getting too complex or delayed, you can add or update rules within the same chat. ChatGPT will update the rules during the chat if you give a clear instruction, so you don't have to restart.

For example, you can say, "Never use long lists from now on." Or you can say, "Always give one-sentence answers until I tell you otherwise." You can also say, "Stop giving steps, just give commands." This direct instruction forces the model to reset its style and process the chat in a simpler way.

This method works because the slowness is related to the amount of text displayed. By adjusting the rules during an active chat, you ease the session and stop the problem before it grows. This is an easy way to manage the session without losing context.

In FireFox, if Firefox displays a message saying "this page is slow" while generating code, you can stop the page, refresh it, and generate the entire code. The server-side generation is complete; the UI update is slow, which can take up to 45 minutes for a single piece of code.

Message to OpenAI

The slowdown in long chats is not caused by the model. It is caused by the way the browser's client-side interface handles long threads. This does not change if you are using Chrome, Firefox, or any other browser. The idea of ​​keeping every message active in the browser, even when the user only needs the last few lines, is counterproductive. The interface also does heavy regular expression checking and code formatting for each block of text.

The solution is to periodically collapse the model, reduce the user’s ability to scroll up (they’re unlikely to do so), and focus on the interaction with the person, not the past history of that chat. That’s the whole idea of ​​context: ChatGPT has context, but the person has their own memory.

The interface design is a weak point that undermines GPT’s capabilities. Experienced users face long waits, frozen screens, and wasted time because the UI doesn’t scale for chats longer than 15 minutes. And either your QA department doesn’t test it, or your management doesn’t listen to QA because experienced users matter. Performance is important.

A few small changes, like collapsing old messages or allowing GPT to archive previous parts of the visible client flow, will go a long way toward solving the problem of slow chat. Don't make excuses - just do it, it only takes a few days of work. That's a fraction of the time a million users spend today.

Preserving context in a new chat

When a chat becomes too slow, sometimes you have no choice but to start a new one. This cleans up the page and gets the system up and running again. But the problem is that ChatGPT forgets everything from the old flow. It forgets module names, design choices, and even the order of steps you've been building for hours. In programming, this can undo four to five hours of progress.

The best way to minimize the damage is to create a backup before restarting. You can ask ChatGPT to create this record for you. Some valid queries:

"Summarize the project so far with all the key steps."

• "List all external file names we've used so far."
• "List all modules we've created in this session."
• "List all environment variables we've defined and their values."
• "List all table names and column details we've created."

Copy the table of contents to a text file on your computer. When you start a new chat, paste the table of contents at the top. If your work uses files, you can also set ChatGPT to create a list of them. Then, place those files into the new chat using the file upload area. This will give the model both the written context and the related files it needs to continue working.

This won't be perfect. The new chat won't remember the details like the old one did. However, the table of contents and the list of files will save you from having to start from scratch. Until OpenAI adds a better way to pass context between threads, this is the only reliable method.

Summary

ChatGPT 5 is a powerful tool that promises speed and expert responses. However, the UI struggles to handle long chats efficiently. The slowdown is caused by the browser, not the AI ​​or the server. The design keeps each message active, runs regular expressions on huge blocks of text, and takes too long to render code.

Your performance will be better if you set rules before you start and update them during the session. You can also protect your work by asking ChatGPT to create summaries, list files, modules, and tables, and then save this record before restarting.

You can use these tips to prevent the worst of the slowdown and keep your projects moving. ChatGPT 5 has a lot of power, but it needs better user interface design to fully unlock its potential.