Bug 428705

Summary:	Choppy and laggy system on NVidia drivers
Product:	[Plasma] kwin	Reporter:	jaromir <j.mir.prazak>
Component:	compositing	Assignee:	KWin default assignee <kwin-bugs-null>
Status:	RESOLVED UNMAINTAINED
Severity:	normal	CC:	nate
Priority:	NOR
Version First Reported In:	5.20.2
Target Milestone:	---
Platform:	Ubuntu
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:

Description jaromir 2020-11-04 23:42:32 UTC

SUMMARY
Everything is slugish unless I force in kwinrc maxfps and refreshrate to 3x my real refresh rate. Most noticible is video playback but also windows animations.

STEPS TO REPRODUCE
1. Test Big Buck Bunny 60fps version on NVidia drivers in MPV (my setups have 60Hz monitors)
2. Change kwinrc file MaxFPS and RefreshRate in composition section to 3x your refresh rate
3. Test the same video again

OBSERVED RESULT
Video is noticibly more fluid with that "hack". Without it, it is really not suitable for any kind of video screening.

EXPECTED RESULT
Video (and overall system animations) are fluid without excesive manipulation with related parameters. 

SOFTWARE/OS VERSIONS 
Linux/KDE Plasma: KDE neon 5.20
(available in About System)
KDE Plasma Version: 5.20.2
KDE Frameworks Version: 5.75.0
Qt Version: 5.15.0

ADDITIONAL INFORMATION
NVidia drivers 450

Comment 1 jaromir 2020-11-05 21:49:11 UTC

After testing kwin in xfce session, I believe, that plasmashell is at fault here. kwin under xfce runs great with composing. under plasmashell..not so

Comment 2 jaromir 2020-11-06 14:48:57 UTC

but, on slihtly less powerfull setup (laptop with nvidia) running kwin under xfce is not really stable. only thing that helps with jittering playback is to turn of composing completely. i do not like this solution, cause composing allows me to move window to another workspaces but to still record screen/window capture them. without it, it losses lots functionally

Comment 3 David Edmundson 2023-09-06 10:38:25 UTC

This bug was reported against an outdated version of KWin. We have made many changes since the. 
If the issue persists in newer versions can you reopen the bug report updating the version number.