Currently I have it set to fixed 60fps. It is a 4k tv which goes up to 60hz and refuses to run at 48hz via custom resolution. So double ratio or 48fps at 60hz will have to do. It's a bit better at x2 but still very noticeable.
Frame interpolation mode: couldn't find it in settings nor in the manual
fi_shader to 10. Is by blocks = 10 or a separate setting?
Arifacts masking I've left on medium for now because it's nearly unwatchable when off
I was unable to set fi_precision to 0.5 from 2, it needs to be an integer.
fi_grid is already 12
fi_scene_changes is an integer, not sure what number that setting is? It's not in the manual.
With these settings it's better but still very noticeable. I normally use svp on Linux and have done for several months and the artifacts have been very minimal on default settings and fixed 60fps. I started using svp on Windows for HDR and that's when I noticed it (although most of the videos I've tried haven't been HDR and that's not related to this issue). Maybe the default settings are different? I also upgraded my R5 2600 to R7 5800X almost exactly at the same time but the system passes all stress tests for a few hours (small FFTs prime95 etc) with the 5800X so I don't think it's instability.