Just installed KDE Neon, insane lag, around 1 fps

I just installed KDE Neon in a partition on my new LG Gram, and immediately I’m getting serious lag. When I move the mouse it takes seconds to respond. Lag is usually caused by running out of CPU or RAM, but this is happening right at startup with nothing else running, and I can see in system monitor that there’s barely any resource usage. This was happening when I booted from USB, and is still happening now that I’m booting from disk. Does anyone know what might be happening or what I can do about it?

update: the problem goes away when I boot in recovery mode, but comes back when I boot regularly.

This is weird but sounds like a hardware support issue - maybe you are in full software rendering mode (though even then it shouldn’t be that bad).

Can you please open the Info Center application, click on “Graphics” and then on “Window Manager” and post here what it says under “Output Backend” and under “Compositing”?

I used my laptop in recovery mode for a while, and I just went back to normal mode and now it works. I don’t know what did it, but my guess is that it was a graphics driver issue and pkcon update fixed it.

in case it’s still interesting:

Output backend
Name: KWin::X11StandaloneBackend

Compositing is active
Compositing Type: OpenGL
OpenGL vendor string: Intel
OpenGL renderer string: Mesa Intel(R) Graphics (RPL-P)
OpenGL version string: 4.6 (Compatibility Profile) Mesa 23.0.4-0ubuntu1~22.04.1
OpenGL platform interface: GLX
OpenGL shading language version string: 4.60
Driver: Intel
GPU class: Unknown
OpenGL version: 4.6
GLSL version: 4.60
Mesa version: 23.0.4
X server version: 1.21.1
Linux kernel version: 6.2
Direct rendering: Requires strict binding: yes
GLSL shaders:  yes
Texture NPOT support:  yes
Virtual Machine:  no
OpenGL 2 Shaders are used

Yea, OpenGL using Mesa on Intel. That should work fine. I agree that it is likely a driver update that fixed it. Good luck, and do give Wayland a try!