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

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:

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

I also tried to disable acceleration in X11. This interestingly enough visibly improved performance of dolphin, but Kmail continues to be bad.