ticked "Modify events" on mouse is causing huge mouse lag with any cpu spike

[yamyoume]

This mouse lag has been bothering me for over a month, driving me crazy, and I couldn’t figure out the cause until now. It turns out the issue was with Karabiner-Elements. When the “Modify events” option is enabled for the mouse under “Devices,” any CPU spike—such as opening a new Chrome tab, loading a website, or accessing settings—causes the mouse to lag.
here's a video demo

When I untick it, the mouse behaves normally again. In the video, it might appear a bit laggy sometimes, but that’s because I’m moving the cursor very quickly, and the video is likely recorded at 30 FPS.

Screen.Recording.2024-12-04.at.11.16.29.PM.mov

[tekezo]

Can you reproduce this issue with a clean profile?
I'd like to determine whether the problem is caused by Complex Modifications.

You can add a profile by following these steps.
https://karabiner-elements.pqrs.org/docs/manual/operation/profiles/#manage-profiles

I'm not sure what mouse you're using, but mice with extremely high DPI might experience this issue.
That said, I don't experience any problems with my mouse, which has a DPI of 8200.
If your mouse has an even higher DPI, reducing the DPI might mitigate the issue.

[yamyoume]

It still occurs even on a clean profile without any complex modifications. This is definitely a new issue. I’ve been using the same mouse (Razer Naga Trinity) for several years and haven’t reprogrammed it since I first got it.

I’m not sure about the DPI settings, but when I access my Windows machine, I’ll double-check the DPI and lower them to see if it makes a difference.

[tonisives]

I had a similar problem. My Logitech m650L bluetooth mouse was quite laggy without enabling it in Karabiner. But when I enabled it in Karabiner, the problem went a lot worse. Mouse was very laggy, almost unusable. Jumped around on the screen, or just lagged alot. When I disabled it in Karabiner, it went back to being a bit better.

I now made a clean install of the system, and installed clean Karabiner. The mouse lag is completely gone. Both with and without Karabiner.

I read from Apple forums that in recent macs/macOS they had problems with Bluetooth devices specifically. I had also problems with my Bluetooth headset lagging. I didn't notice that my problem was related to CPU spikes specifically.

MacOS Sequioa 15.2 (24C101)
Karabiner 15.3
Macbook M3 Pro

[yamyoume]

mine is a wired mouse (perfectly fine without enabling in Karabiner).
TBH i've been thinking of resetting my Macbook pro as it's a base 14" M1 bought at launch in 2020 and my idle CPU is 30% 😭 or 50% when spotlight is indexing which happens a lot.