Yeah, not sure what's going on there. Some of it is probably the model running, but the interface itself seems to be ridiculously bloated. Like, an order of magnitude worse than Slack in its worst days.

In fact, ChatGPT is unusable on my phone (Galaxy S22, Firefox), as it visibly slows down with every word it outputs, so it takes a minute for it to print out a full paragraph of text. I haven't explicitly debugged it, but comparing with PC experience of the same site, it's rather clear that it's not the AI that's lagging, but whatever mess of JavaScript they have running on the website itself.