ChatGPT-5 has memory... so do you even need a custom GPT?

There’s a lot of buzz right now about ChatGPT-5 and its improved memory.

August 28, 2025 • Estimated Reading Time: 2 minutes

The big question I keep hearing is:

“If it remembers everything, do I even need a custom GPT anymore?”

Here’s the reality:

Yes, the memory is better.

But it remembers everything across every chat. Which sounds great… until you realise what that really means.

👉 You’ll hit the context window pretty quickly.

👉 It only holds parts of the information.

👉 Then it starts predicting to fill in the blanks.

That’s where things get messy.

Why custom GPTs still matter:

Custom GPTs operate in a silo.

They don’t try to remember everything you’ve ever said. They only reference the information you give them.

That means:

  • You can upload far more detail via a knowledge base than GPT-5’s memory could handle.

  • They’ll reference that information every single time before giving you an answer.

  • They’re reliable for tasks where accuracy really matters.

For example, if you want a customer support agent GPT that needs to handle:

  • Privacy policies

  • Delivery policies

  • Terms & conditions

  • Returns processes

ChatGPT-5 will forget parts of that over time.

A custom GPT won’t, because it pulls fresh from the source on every prompt.

Here’s the bottom line:

ChatGPT-5’s memory is a big step forward. But if you want accuracy on specific roles or processes, custom GPTs are still the better tool.

Think of it this way:

  • Memory = useful for general conversations

  • Custom GPT = reliable for specialist tasks

And in business, reliability beats hype every time.

– Dean & Felicity