nearly 100% graphics pipe of Rx570 usage when using certain applications

[Marek Kochanowicz]

I am running Arch linux with kde 5.25 

Graphics:
  Device-1: AMD Ellesmere [Radeon RX 470/480/570/570X/580/580X/590]
    vendor: Sapphire driver: amdgpu v: kernel arch: GCN 4 process: GF 14nm
    built: 2016-20 pcie: gen: 2 speed: 5 GT/s lanes: 1 link-max: gen: 3
    speed: 8 GT/s lanes: 16 ports: active: DP-2
    empty: DP-1, DVI-D-1, HDMI-A-1, HDMI-A-2 bus-ID: 25:00.0
    chip-ID: 1002:67df class-ID: 0300
  Device-2: Logitech C920 HD Pro Webcam type: USB
    driver: snd-usb-audio,uvcvideo bus-ID: 1-1:2 chip-ID: 046d:0892
    class-ID: 0102 serial: 05788D2F
  Display: x11 server: X.Org v: 21.1.3 with: Xwayland v: 22.1.2
    compositor: kwin_x11 driver: X: loaded: amdgpu gpu: amdgpu display-ID: :0
    screens: 1
  Screen-1: 0 s-res: 3840x2160 s-dpi: 96 s-size: 1016x571mm (40.00x22.48")
    s-diag: 1165mm (45.88")
  Monitor-1: DP-2 mapped: DisplayPort-1 model: Samsung LU28R55
    serial: H4ZRC00046 built: 2021 res: 3840x2160 hz: 60 dpi: 154 gamma: 1.2
    size: 632x360mm (24.88x14.17") diag: 727mm (28.6") ratio: 16:9 modes:
    max: 3840x2160 min: 720x400
  OpenGL: renderer: AMD Radeon RX 570 Series (polaris10 LLVM 13.0.1 DRM
    3.46 5.18.7-arch1-1)
    v: 4.6 Mesa 22.1.2 direct render: Yes


Some KDE applications are bordeline unusable currently. Especially kmail. Even 
changing directory is very slow and resizing the kmail window is a sure way to 
produce graphic pipe usage spike in radeontop to 100%. Drag select in dolphin 
is sluggish. Disabling kwin composition, or even launching appliaction under 
fluxbox does not improve situation. Same problems are observed under 
kwin_wayland. I also tried to use lower resolution monitor but it was only 
slightly better. Firefox and other non-qt application appear to work fine.

-- 
Marek Kochanowicz