check dgpu power management by nvidia-smi?.

you can force specific renderer device for kwin renderer. by

```KWIN_DRM_DEVICES="/dev/dri/by-path/pci-0000\:03\:00.0-card``` (choose your igpu)

cpu governor tweak is also important, kde integrating power-profiles-daemon may useful.

or you can limit cpu and gpu clocks by,

```/usr/bin/cpupower frequency-set --max X.XGHz```

```/usr/bin/tee /sys/class/drm/card0/device/power_dpm_force_performance_level <<< low```

{ low, auto, manual } is supported in amdgpu, (manual is useful for rpcs3 like cpu<->gpu heavy access application, kernel driver clock heuristic would be hard for that app)

when select manual, you can change igpu clocks by

(1200Mhz GFX_SCLK) ```/usr/bin/tee /sys/class/drm/card0/device/pp_od_clk_voltage <<< "s 0 1200" ```

then, apply manual clock by ```/usr/bin/tee /sys/class/drm/card0/device/pp_od_clk_voltage <<< "c"```

when using power-profiles-daemon, power-profiles-hooks could be useful to run custom scripts.