PMS not using all available network bandwidth




All of a sudden my Plex server isn't using all the available network bandwidth for streaming. As an empirical observation only half of the 100Mbps wired link is used, roughly somewhere between 5-6 MB/s out of the max(theoretical) 12.5 MB/s. My Plex has been using all the bandwidth (10-11 MB/s) for month before this issue - I've been noticed it when rewatching a 4k remux (60-70 Mbps bitrate) which played very smooth in the past, but now stutters buffering every 5-10 sec. Has anyone experienced this issue so far?

My setup below:
Server: latest Plex ARM64 version available from for RPI3 - wired network 100 Mbps, 4TB USB Hdd storage
Device: XPLAY (direct play/stream, no transcoding) on LG 55EG920V TV - wired network 100 Mbps
Network: wired 100Mbps cat 5e router/switch

I can copy files (scp/smb) from RPI3 at ~10 MB/s and a speed test on the TV's browser gave me almost identical result. On the RPI3 I measured the bandwidth with speedometer and the CPU never rose above 25% during streaming.

As a conclusion the TV and RPI3 can transfer at 10 MB/s, but Plex only streams at half that speed. All the movies (4k or 2k) with a bitrate less than 5 MB/s would play smooth enough, while those exceeding 5 MB/s stutter buffering.

King regards,


@“Mihai B.”
Please don’t crosspost. One thread is enough. Your thread would have been moved into this section, anyway.



I fix the issue but unfortunately I didn’t find the root cause of the problem.

Last evening I made a test with a PMS instance I have on my laptop(win32) for testing purpose only:

  • on the RPI I stopped all the services with access to the USB storage, including PMS, then I dismounted external drive
  • next I plugged external drive into the laptop to serve as media library
  • on the TV I changed the PMS server(win32) in XPLAY and started to watch a 4k remux which played very smooth without stuttering; network usage on the laptop was between 9-11 MB/s, as it was on the RPI before the issue
  • then I put external drive back on the RPI, started the above services, changed back the PMS server(rpi) in XPLAY and watched the same 4k remux, and surprise, network usage was the same as before the issue, 9-11 MB/s

I don’t know for sure which change was effective, but my best guess is the server switch in XPLAY did the trick.


PS. my apologies for crossposting, I saw the RPI section after the initial post on the linux section