Plex server (on PC) unable to transcode 4k mkv files - Roku player

Plex Players
1

My plex server is on a PC (i5-7200U CPU @ 2.50GHz 2.70 GHz) 8GB RAM.
When I try to play 4k UHDBlu Ray rips (mkv) files, the player (Roku ultra) buffers terribly and finally gives message that server is not powerful enough to process the playback.

I have Plex Pass, but will unsubscribe if I can’t play 4k rips.
Roku Ultra is hardwired to the PC (Plex server) - not wifi.

Please advise server settings.

2

If by chance you are trying to play an HDR rip on a SDR display, that asks the server to do tone mapping. A Windows Plex server cannot take advantage of Quick Sync tone mapping either.

Maybe that’s not your setup, but it would explain it.

3

Same experience separate Roku ultras (4k) connected to a 1080p TV -
and a 4k projector.