Chat slowdown after many agent chats?

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1

Over the last few months of Cursor updates, I’ve noticed a pattern that’s making the product hard to rely on for day‑to‑day work.

Once the number of agent conversations grows (I don’t have an exact threshold, but it’s clearly “a lot”), performance drops off a cliff. The whole IDE starts to feel almost frozen, and the chat UI in particular becomes unusably laggy — think early‑2000s desktop sluggishness, not “a heavy project.”

What stands out is that this seems especially bad when using an non-English IME for CJK input. The app then behaves in a way that reminds me of buggy, un‑sanitized output: stutters, long pauses, and a general sense that the UI thread is drowning.

My machine is nothing exotic: 13th‑gen Intel i7, mainstream RAM, normal SSD — the kind of setup that should handle an editor comfortably. it feels like a scaling or rendering/input bug that shows up as chat history or agent state grows.

I can’t comfortably leave Cursor open for long sessions, and old chats feel like they’re punishing me for keeping them — as if the only workaround is to let to be history start fresh, which shouldn’t be the intended workflow.

-Windows user

Thanks.

3

Hey, this is a known issue. Chat history and agent state can build up over time and really slow down the UI. A few users have reported the same thing.

A couple of things to check and try:

  1. Check your state.vscdb size. This database stores chat history and can grow without limits. Run this in PowerShell:

    Get-Item "$env:APPDATA\Cursor\User\globalStorage\state.vscdb" | Select-Object Length

    If it is multiple GB, that is probably the cause.

  2. Quick workaround: delete old chat history. Open Command Palette with Ctrl+Shift+P, then run Delete Old Chats. This clears old conversation data without touching your settings.

  3. Nuclear option if that does not help: clear Cursor caches fully. Back up your settings first, then remove these folders:

    %APPDATA%\Cursor\Cache
%APPDATA%\Cursor\CachedData
%APPDATA%\Cursor\Code Cache
%APPDATA%\Cursor\GPUCache

  4. Diagnostics: when the lag happens, open Process Explorer via Ctrl+Shift+P, then run Developer: Open Process Explorer, and check which processes are using the most memory.

About the CJK IME part: that is interesting and could point to a rendering bottleneck. The team knows about chat performance scaling issues and some IME quirks.

Can you also share your Cursor version? Go to Help > About > Copy, so I can check if you are on the latest.