[KDE Plasma 6.7.1] Huge GPU spikes and lag when in fullscreen programs

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1

Hey there everyone, so I recently got a new PC and installed Fedora 44 KDE on it. It’s an all AMD build - 6800 XT GPU, 9800X3D CPU, and 32GB of DDR5 RAM.

I am having a very odd issue I didn’t previously have where, when I am in a fullscreen program (for example Firefox or a video game), interacting with the system becomes laggy and spikes my GPU up hugely.

I was able to test this by opening the Monitor app, fullscreening it, and then launching Dolphin. I saw for a brief second my GPU spiked to 48.5% usage. Same thing happens when interacting with the System Tray or hitting the Super key while in a fullscreen app. The animations appear very laggy. Same when making an app fullscreen, the animation lags.

Adaptive sync is disabled by default. Enabling or disabling it doesn’t change anything, which is the only advice I was able to find online for similar issues.

Anyone know if this could maybe be an issue with hardware or a bug with Plasma? At a loss, particularly since the GPU is the same as in my old build. I just took my 6800 XT from my old PC and chucked it in this newer AM5 build.

2

Cannot replicate.

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KDE monitor running, opened Dolphin where that small lump appears in the top CPU graph directly above the Core 4, 10 and 16 column. There’s a tiny blip in GPU usage as the window is drawn into the frame buffer. Same thing observed with other programs, some being more heavy than others (Pycharm for example, sucks up a lot of CPU on startup as does RustRover, but it’s obvious what these are doing to require the CPU cycles).

When you see these large spikes what is Dolphin opening in to? Is if, for example, starting up by viewing a directory with 8000 photographs in it and rendering thumbnails for example?

Do you see anything in the journal when it starts up?

If you really want to get into the weeds, you can run dolphin like so QT_LOGGING_RULES="*.debug=true" dolphin >dolphin.log 2>&1 and then read through the dolphin.log it’ll create in the current directory, but be prepared for a large amount of output - how useful it’ll be to you is debatable.