Bug 483038 - Screen set to 60Hz but renders at 30FPS
Summary: Screen set to 60Hz but renders at 30FPS
Status: REPORTED
Alias: None
Product: kwin
Classification: Plasma
Component: performance (show other bugs)
Version: 6.3.3
Platform: Arch Linux Linux
: NOR normal
Target Milestone: ---
Assignee: KWin default assignee
URL:
Keywords: qt6
Depends on:
Blocks:
 
Reported: 2024-03-09 21:19 UTC by Miroslav Jarý
Modified: 2025-03-15 08:18 UTC (History)
4 users (show)

See Also:
Latest Commit:
Version Fixed In:
Sentry Crash Report:


Attachments
Output of wayland-info (12.42 KB, text/plain)
2025-03-15 08:14 UTC, Miroslav Jarý
Details
Performance stats when display set to 60Hz (140.58 KB, patch)
2025-03-15 08:15 UTC, Miroslav Jarý
Details
Output of drm_info (344.08 KB, text/plain)
2025-03-15 08:17 UTC, Miroslav Jarý
Details

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Description Miroslav Jarý 2024-03-09 21:19:34 UTC
SUMMARY
***
NOTE: If you are reporting a crash, please try to attach a backtrace with debug symbols.
See https://community.kde.org/Guidelines_and_HOWTOs/Debugging/How_to_create_useful_crash_reports
***
When I set my internal screen to 60Hz, the "Show FPS" desktop effect shows consistent 30FPS, and the image feels laggy. When set to 144Hz, Plasma shows correctly 144FPS. This issue appears only in Wayland; in X11 the rendering is just fine.

STEPS TO REPRODUCE
1. Open "Configure display settings..."
2. Set monitor (internal/external) refresh rate to 60Hz.
3. Confirm changes

OBSERVED RESULT
Desktop effect "Show FPS", external tools and personal observation shows that the rendered screen is in 30FPS and feels laggy.

EXPECTED RESULT
The monitor will render at the same FPS as the refresh rate set in settings.

SOFTWARE/OS VERSIONS
Operating System: Arch Linux 
KDE Plasma Version: 6.0.1
KDE Frameworks Version: 6.0.0
Qt Version: 6.6.2
Kernel Version: 6.7.9-zen1-1-zen (64-bit)
Graphics Platform: Wayland
Processors: 12 × 13th Gen Intel® Core™ i5-13420H
Memory: 15,3 GiB of RAM
Graphics Processor: Mesa Intel® Graphics
Manufacturer: LENOVO
Product Name: 82XV
System Version: LOQ 15IRH8

ADDITIONAL INFORMATION
Comment 1 Dāvis 2024-03-11 12:10:39 UTC
I just tested this with AMD Vega 64 using amdgpu driver and I don't have such issue. Works correctly in all refresh rates: 60 Hz, 72 Hz, 75 Hz, 85 Hz, 96 Hz, 100 Hz, 120 Hz, 144 Hz, 180 Hz.

So this looks something specific to your setup/GPU/monitor. Maybe you can try different monitor and see if it makes any difference to rule that out.
Comment 2 Miroslav Jarý 2024-03-11 18:57:30 UTC
I cannot confirm it with different PC, but it can be replicated with multiple monitors; via USB-C or HDMI.

For clarification; I believe that the external monitors are using my dedicated Nvidia RTX 4050 (as when I disable it the monitors no longer work).
Comment 3 leo5t 2024-03-12 13:18:42 UTC
I experience the same behaviour.

Operating System: Arch Linux 
KDE Plasma Version: 6.0.1
KDE Frameworks Version: 6.0.0
Qt Version: 6.6.2
Kernel Version: 6.7.9-arch1-1 (64-bit)
Graphics Platform: Wayland
Processors: 4 × Intel® Core™ i5-2500K CPU @ 3.30GHz
Memory: 11,7 GiB of RAM
Graphics Processor: NVC1
Manufacturer: MSI
Product Name: MS-7673
System Version: 1.0
Comment 4 Miroslav Jarý 2024-04-02 11:25:59 UTC
I can confirm this is still an issue on Plasma 6.0.3.
Comment 5 Zamundaaa 2024-04-02 11:47:16 UTC
*** This bug has been marked as a duplicate of bug 452219 ***
Comment 6 Miroslav Jarý 2024-09-09 13:16:26 UTC
Hey there!
After further investigation, I don't think this is marked properly. I can reproduce this issue even with my integrated monitor and while disabling the Nvidia graphics in the BIOS. It seeems that the bug is present on Intel iGPUs too.
Comment 7 Zamundaaa 2025-03-11 19:01:46 UTC
Do you still have this issue in Plasma 6.3? If so, please attach the output of drm_info and wayland-info here and record a performance log (with https://invent.kde.org/plasma/kwin/-/wikis/Environment-Variables#kwin_log_performance_data) and attach that here
Comment 8 Miroslav Jarý 2025-03-15 08:14:03 UTC
Confirming that this is still an issue on Plasma 6.3.3.
Attaching info as requested.
Comment 9 Miroslav Jarý 2025-03-15 08:14:36 UTC
Created attachment 179414 [details]
Output of wayland-info
Comment 10 Miroslav Jarý 2025-03-15 08:15:04 UTC
Created attachment 179415 [details]
Performance stats when display set to 60Hz
Comment 11 Miroslav Jarý 2025-03-15 08:17:53 UTC
Created attachment 179416 [details]
Output of drm_info