Simple 3D applications like glxgears with 4K resolution has bad performance on Oland [1002:6611]

Throttled to power level 0 after running simple 3D applications for a while: $ cat /sys/kernel/debug/dri/0/radeon_pm_info uvd vclk: 0 dclk: 0 power level 0 sclk: 30000 mclk: 15000 vddc: 900 vddci: 800 pcie gen: 3

Only radeon has this issue, amdgpu doesn't have this issue. Later I identify the firmware is what matters here.

Once switching to firmware from amdgpu directory, the issue is also gone for radeon.ko.