Server Version#: 1.27.1.5916
Player Version#:All
Every time some one start player a video in a format lower then the original, the NAS run at 100% and it seam that plex is not using the hardware transcode. i have a TerraMaster F4-422 with TOS 5. The version right now is 5.0.129. With TOS 4.2, it was running perfect. And yes hardware transcoding is enable.
Any details about how those videos are being streamed (e.g. using the Now Playing information from the server dashboard)? HW transcoding cannot handle all possible use cases – e.g. if there’s subtitles to be burned into the video, that’ll require the transcoding to fallback to the CPU.

i think you did not read my message properly or i did not explaine it clearer.
With version TOS 4.2, transcoding was taking 10% if my F4-422 NAS resource. So at least 7 people could stream from my server with transcoding without any problem. But now with TOS 5, the same video will take 100% of my nas resource. With two people, it will not work properly. That why i think that with TOS 5, the hardware transcoding is not working. All test i did is with the same video.
And if i roll back my NAS to TOS 4.2, PLEX will not work at all. So i’m stuck with TOS 5.