That was the piece I had been missing… you hadn’t mentioned you’re using the Roku as your playback device. What Roku model is that if I may ask?
There’s two sides to that. The first is the player’s capability do deal with 4K material. If the player cannot deal with what it’s presented with, it’ll ask the Plex Media Server to transcode the media to a format it can digest.
4K content is generally tricky as it’s quite demanding on your player. And also because transcoding it requires a massive load of CPU power (or a server with a sufficiently capable CPU/GPU to do the transcoding).
Long story short… the ReadyNAS will likely not be able to transcode your 4K content if needed. With regards to your laptop… it’ll depend on what HW is built into that device (e.g. CPU/GPU).
Also keep in mind that the media itself is not necessarily to blame. The stuttering could also be due to a poor network connection (again… 4K material is very demanding when it comes to that).
I strongly recommend to have a look at this forum thread discussing 4K playback:
