But the longer I use it, the slower it gets. After just a few hours of use, it can’t even type; sometimes a letter appears 2 seconds after I press the keyboard. IDE becomes very laggy.
There’s no other way than to close the app and start it again - and then it’s fine again. But I have to do it 2-3 times per day - so seems like there’s a memory management issue.
I have a MacBook Pro M4 Max, so the hardware is definitely sufficient.
Steps to Reproduce
Open Cursor
Use AI agents
The more you use it, the slower/laggier it gets
Restart and repeat
Expected Behavior
It should work as fast as on the startup, even days or even weeks.
Operating System
MacOS
Current Cursor Version (Menu → About Cursor → Copy)
This looks like a memory leak or a process issue. Let’s check a few things:
Extension Monitor: Settings > Application > Experimental > enable Extension Monitor, then CMD + Shift + P > Developer: Open Extension Monitor. Which extensions are using the most resources?
Process Explorer: CMD + Shift + P > Developer: Open Process Explorer. Check the extensionHost and ptyHost processes when Cursor starts lagging. How much memory are they using?
Quick test: Try running cursor --disable-extensions from a terminal and use it for a few hours. Does the issue still happen?
Haven’t tried that one, but since usage is low, not even 1 GB, I don’t think it will have any effects.
4. I’m not using MCP.
5. Extra info
The codebase is massive - a big monorepo with 30-ish Next.js projects inside, plus 20-ish reusable packages. 850k+ lines of code (not counting node_modules and similar, with them is way more)
With agents, I sometimes have 2-3 running at the same time, but often only 1.
Chat history can sometimes be long, depending on the task/feature.
I keep the same agents running only if my prompts are related to the previous context. As soon as I’m done, a new chat is opened.
I also close chats now as soon as I’m done, but that doesn’t help.
Before, I never closed any chats - had tons of them at the same time - no problems.
Thanks for the screenshot. I can see <ext-host-runtime> is taking 99,64% of Extension Host time, that’s interesting.
A few questions and steps:
Activity Monitor: Open Activity Monitor (macOS) and find the Cursor/Electron processes. What does memory usage look like when the IDE slows down? Extension Monitor shows only 326 MB, but real usage could be higher.
Test without extensions: Given the size of your monorepo (850k+ lines), it’s worth testing. Run cursor --disable-extensions and use it for a few hours. This will help confirm whether the issue is tied to Extension Host or something else.
.cursorignore: For a monorepo this large, I recommend adding a .cursorignore file to exclude unnecessary directories from indexing (node_modules, build artifacts, etc.). This can significantly reduce load.
This is a known issue for large codebases, and the team is working on optimizations. Let me know what you find from the tests.
Unfortunately, today is a very bad day - Cursor gets very slow very fast - sometimes even after 10 minutes. It’s almost getting unusable at some point take more than 5 seconds for text to appear on screen after typing. (everything else on my laptop works blazing fast)
I’ll try cursor --disable-extensions - last shot!
Here’s my activity monitor and all Cursor-related things:
I see in your Activity Monitor screenshot that Cursor Helper (Renderer) is using 1.06 GB, which is a lot.
From your recent posts, it looks like things are getting worse, now it gets slow after about 10 minutes. This is a known issue with large monorepos, and the team is working on a fix.
Next steps:
Test cursor --disable-extensions like you planned. This is the key test to see if the Extension Host is the cause.
Can you share your .cursorignore contents? I want to make sure all the important directories are excluded (node_modules, .next, build, dist, etc.) for each project in the monorepo.
What extensions do you have installed? (Settings > Extensions)
Temporary workaround while you test: if disabling extensions does not help, try working with one project at a time. Open a specific folder inside the monorepo instead of the repo root. This should reduce indexing load.
Waiting for the results from the no extensions test.
Unfortunately, cursor --disable-extensions doesn’t make a lot of difference - I only have 7 basic extensions installed (image below).
Loading 1 project at a time is not really an option due to the monorepo architecture. Many projects are interconnected, and losing AI awareness over all of them would make things much slower.
I hope the team will fix it - it should be possible, especially because there’s a ton of free RAM & CPU to use. Good luck!
take more than 5 seconds for text to appear on screen after typing. (everything else on my laptop works blazing fast)
