Choppy UI performance when using mouse

[RoelJuun]

Since upgrading to Big Sur from Mojave I noticed something strange and annoying on my 13 inch 2015 MBP. Moving windows or clicking buttons is really choppy, frames drop all the time when grabbing a window and moving the window around. It doesn't happen all the time, sometimes for a few seconds things work fine until they suddenly don't.

I use my MBP with a 27 inch ACD. When I disconnected my external monitor to do PRAM/VRAM/SMC-resets the performance was suddenly buttery smooth. I noticed this was because I used the built in trackpad. Then I tried it with my external trackpad and performance was smooth too. Only when using my mouse (Razer Deathadder) the system crawls.

I installed the OS again but it didn't help. I changed some settings for my mouse in System Preferences but it doesn't help.

Does anybody have any idea of what might cause this strange behaviour?

 

[anzio]

Yeah. It's an issue with WindowServer in Big Sur when using wired mouse, from what I seen. You can check Console.app and see WindowServer go crazy when you move a mouse rapidly.

I submitted feedback through Feedback Assistant, and I'd suggest you do the same 🙂. It's very weird.

 

[mouthster]

Yeah when I wiggle the mouse I see WindowServer shoot up to 120% CPU usage. I guess everyone at Apple uses Magic Trackpads. (Also using a Deathadder)

 

[RoelJuun]

Thank you for your input, I will send feedback to Apple. It's ridiculous that something so important doesn't work in a new version of an OS.

 

[anzio]

Preliminary testing shows that this seems to be fixed in macOS Big Sur 11.1 for me.

 

[RoelJuun]

For me too, very happy. WindowServer still jumps to about 40% but there is no stutter anymore.