here are my log fil and a screenshot of ctrl - J.
I have reseted my bios, reset to uefi, which is the way to do this to get default cpu bios setting. Youtube is behaving a bit bette now. not so much stuttering and less loading time.
But JRiver is behaving the same and that is more specifically when I move the mouse during playing a movie(local 4k hdr movie) and then the movieplay hangs and when then when the panel on the top of the screen fades away again after not moving the mouse it also get a hang and then renders on normally. so this is not periodically but reproduceable, it happens everytime I touch the mouse and right after the panel fades away again. I also moved the movie(alien covenant) to the system ssd disk and no change in behaviour of playback.
On JRVR it looks like I only get framedrops and repeated frames only when I use the mouse and rigth after the panel fades away. I also tried to with and without video clock and hardware accelerating video decode ticked, same result.
when it comes to skin I use one JRiver not third pary and I also dont use plugins or anything else. I use JRiver for local movie files and music files, no auto import.