Server Version#: 1.13.9.5439
Transcoding cannot keep up with any UHD HEVC file, but there does not actually appear to be any bottleneck in any of the hardware. The CPU sits at ~30%, memory is fine, disks are not under heavy load, transcoding temp files are into a ramdisk.
It seems that the plex transcoder is only using 12 or so threads, and so is letting the rest of the CPU idle whilst streams fail to play back without spending half their time buffering because transcoding speed hovers around 0.5.
It has been a while since I last tried to transcode a UHD file (they are usually direct played), but I am fairly certain that this server used to handle them without any issue a few months ago.
