Entire Cursor IDE slows down when chat transcript gets long

Describe the Bug

Hey all — noticing a pretty significant performance issue in Cursor.

Whenever the chat transcript with the AI gets long (especially after a few hundred messages), the entire IDE starts to lag: typing slows down, file navigation gets choppy, and even basic actions like saving or scrolling start to stutter. It feels like the transcript rendering or memory usage is degrading the whole app’s responsiveness.

When closing the Cursor chat tab on the right, the entire IDE speeds up again.

Tested on a MacBook Pro (M3, 32GB RAM), latest Cursor version. Issue persists across multiple projects.

Would be great to know if anyone else is seeing this or if there’s a known fix/workaround. Happy to share more info if helpful.

Thanks!

Steps to Reproduce

Open Cursor IDE and start a new or existing project.

Open the Chat sidebar and begin a conversation with the AI assistant.

Continue chatting until the message count reaches ~100+ (or scroll through a long existing transcript).

Try performing typical development actions:

Typing in a code file

Scrolling through large files

Opening/closing tabs

Navigating the project tree

Observe significant slowdown across the entire IDE — not just the chat pane.

Operating System

MacOS

Current Cursor Version (Menu → About Cursor → Copy)

Version: 1.3.9
VSCode Version: 1.99.3
Commit: 54c27320fab08c9f5dd5873f07fca101f7a3e070
Date: 2025-08-01T20:07:18.002Z
Electron: 34.5.1
Chromium: 132.0.6834.210
Node.js: 20.19.0
V8: 13.2.152.41-electron.0
OS: Darwin arm64 23.3.0

Does this stop you from using Cursor

No - Cursor works, but with this issue

@emperor, welcome to Cursor Forum.

Thank you for your bug report. We are working on performance improvements and will release them as version 1.4.x soon

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