Bug 467610

SUMMARY
On my regular 1080p displays, window resizing is smooth. Effects like Dolphin's F3 splitscreen view are very smooth even when the window is maximised. However on my 4k@150% scaled display, once windows go above a certain size, their resizing starts to get choppy and the aforementioned Dolphin effect is also choppy. The larger the window, the choppier the effect.

Out of curiosity I decided to try and resize a window across three of my 1080p displays, and once the window hit a certain size, resizing started to get choppy and the F3 effect also got choppy.

This is a specific KDE application so it may not be related, but Spectacle is also a bit choppy when activating the region select. Dragging this doesn't happen when my 4k scaled display is turned off, so perhaps the choppiness of that effect is also related to the scaled display/window sizing issue.


STEPS TO REPRODUCE
One example:
1. Maximise Dolphin on a 4k@150% scaled display 
2. Press F3 to activate the split-screen effect
3. The bar moving from the right-hand size to split the file list will appear much choppier than it would on a regular 1080p display

Similar choppy behaviour can be observed when resizing windows that would not normally be choppy at their default size. Different windows have different thresholds for when they start to become choppy. For example, Konsole needs to be almost completely covering the screen before it starts to exhibit choppy behaviour. Dolphin only needs  to be a little larger than it would be on a 1080p display.

OBSERVED RESULT
Some KDE animations are choppy.


EXPECTED RESULT
KDE animations should be smooth (when adequate hardware is used of course)


SOFTWARE/OS VERSIONS
Linux/KDE Plasma: 6.2.6-zen1-1zen
KDE Plasma Version: 5.27.3
KDE Frameworks Version: 5.104.0
Qt Version: 5.15.8

ADDITIONAL INFORMATION
I would consider myself to be running a fairly capable PC (I primarily use it for gaming) so I don't think my hardware should be a bottleneck here really, but I will list it in case there is some sort of issue with my hardware:
- CPU: Ryzen 7 3700X
- GPU: AMD 5700XT 8GB
- Drivers: Mesa 22.3.6
- RAM: 32GB

I also want to emphasize that is such an incredibly minor "issue". I am only reporting it as it would be an awesome quality-of-life improvement.

Only tested on Wayland, have not tried X11. This is also not "new" behavior, I recall this since at least Plasma 5.24 which is around when I started using Wayland full-time. This is just my first reporting of it.