Been having this issue with KiCad for some time now. Performance in the PCB editor is okay when zoomed out, pretty much 60 FPS at 4k. When zooming in it gets very slow, down to 1-2 FPS.
Fallback graphics are a consistent maybe 5 FPS at all zoom levels.
I’ve tried turning layers on and off, as well as other visual settings. Hardware acceleration is enabled. Simple boards are okay, but the one I’m working on (unfortunately commercial or I’d post it) is very slow. It makes routing and moving stuff difficult, it’s so bad.
My CPU is a Ryzen 7800X, so fairly modern and powerful. I know that Intel Arc can have some issues, but it’s weird that they only happen when zooming in.
I think that normally refresh rate increases a bit when zooming in, because less objects have to be rendered. More complex PCB’s also render slower. I usually use the Olinuxino A64 Rev C as a benchmark. It’s on github, and linked to from the “Made with KiCad” section on the KiCad website (“Boatcontrol” is the slowest to render accessible project that I know, but the Olinuxino already is more complex then anything I am liable to make myself).
Maybe it is project related. KiCad really struggles with some constructs, such as graphics with lots of vectors. Have you tried other projects?
I just checked again, an I’ve got the feeling KiCad may have become quicker here, I do not see any noticeable lag while panning or zooming though the Olinuxino A64 Rev C. Redraw is faster then my eyes can observe.
And I’m running Linux on a Ryzen 5600G, which has quite moderate performance.
One thing you should definitely check though is whether you have the latest and greatest graphics drivers. Apparently KiCad uses some of the more “obscure” parts of OpenGL and bugs in those rivers tend to hang along for a long time.