On a 40 series GPU, if frame generation is not forcefully disabled in some way (WINEDLLOVERRIDES="sl.dlss_g=d”, DXVK_NVAPI_GPU_ARCH=GA100, PROTON_HIDE_NVIDIA_GPU=1), the game microstutters a lot regardless of frame gen being turned on or off.
It was first discussed on dxvk-nvapi github: ARC Raiders frame generation availability causes microstutters · Issue #336 · jp7677/dxvk-nvapi · GitHub
The most notable things is this log which gets repeated a lot, although it stops at some point. Might be unrelated to the microstutters.
info:nvapi64:<-NvAPI_D3D_SetSleepMode (Enabled/0us): OK
info:nvapi64:<-NvAPI_D3D_SetSleepMode (Enabled/4166us): OK
Also, if gamescope is not used, with framegen on fps permanently drops to about half and it can only be fixed by restarting the game.