I had ongoing issues with playback stutters on my Q80R QLED TV when playing files via Plex or from USB and I have stumbled onto the solution and thought I would share.
I would get stuttering every couple of second when playing back specific samples of different content. I realized the commonality between the samples was the amount of subtitle tracks. The files could have been H264 or H265 encoded. However if the files had a subtitle track for every language it would not playback smoothly. I discovered if you simply remove the subtitle SRT files they would playback perfectly. I for example and playing a lot of .mkv files and was able to remove the subtitle tracks using a MKVToolNix GUI. Give it a try if you experience any issues.
Just thought I'd share since it was causing me a lot of frustration.
