Plex is suddenly buffering

Server Version#:
Player Version#:
<If providing server logs please do NOT turn on verbose logging, only debug logging should be enabled>

I have a Synology DS923+ system, and play the material via LEAP-S3 Android TV-Box 4K Google TV. My internal network consists of Asus RT-AX89X with a 250/250Mbit/s conection and cat6a 500mhz wires between all devices according to all the rules of the art.
When I measure via speedtest.com I have 250/250Mbit/s, and when measuring internally in my system I have 1Gbit/s…so now to the problem.

I’ve had Plex for about a month, and it worked very well at first. But since last week I experienced that Plex “stuck” in the synchronization somehow, and the Activity was spinning for several days without interruption. I then updated to the latest Plex media server software, and restarted the NAS.
Since then Plex has been buffering constantly every 20sec when playback, and sometimes sending messages that my network is slow.
All other streaming is fine, so it’s just the app for Plex that’s having problems.
Pleace help

Can you please do the following:

  1. Go into Settings - server - General - Show Advanced
  2. Make certain DEBUG logging is enabled and VERBOSE is disabled
    – SAVE if you make changes
  3. Now restart Plex

At this point, if it starts “Sync” and “Spinning activity” by itself,
then let it run for a couple minutes. This will give it time to write enough to the logs so we should be able to figure out what it’s doing

If it doesn’t start doing it on its own, do whatever you need (and tell us) to make it happen. Again, let it run for a couple minutes

Now download the server’s log files
Setting - server - Troubleshooting - Download Logs

It will give you a ZIP file to attach here

So we have a better understanding please give us an indication of how much of each media type you have ; Movies, Episodes, Photos, and Music.

Hello
The settings were already made, so I didnt change any settings
I attach the logs below

Plex Media Server Logs_2025-04-24_23-40-03.zip (4.2 MB)

I have around 10 TB of film, 0,7 TB music, and no photos (I took away the photos since i couldnt make it work).

Jonas

@JonasEdvardsson

I can see what’s happening.

There is a lot of playback activity , with software transcoding ( the Ryzen CPU has no HW GPU for transcoding )

Between the playback transcoding, and the usage sync, it’s busy

It also looks like you just added a lot of media. Is this true?
( I see it generating a lot of Chapter Thumbnails – CPU intensive )

Ok, so what does this mean for me regarding the hardware in my NAS? Is there anything I can adjust my settings to improve performance?

What do you mean by recently? In the last week I’ve added about 15 movies.

15 movies shouldn’t cause the amount of activity.

Did you recently upgrade PMS version from a version below 1.41.5 ?

I’m asking because the amount of activity I see is showing work which should have already been done — unless – you just upgraded and it had not previously been done (perhaps a library setting?)

Playing to Android devices hides a lot of the info about what’s happening.

When you play to the browser (Plex/web) do you get the same buffering?

I don’t know what version I had before the one I have now (Version 1.41.6.9685), but I did an update a week or so ago.

When I thought the library was constantly updating itself, I made a change in the settings to NOT change the library automatically, but only when changes have been detected in a folder.

When I run from plex/web, it’s the same. I can see that the CPU in DS923+ goes from 2% to 96% when I press play on one HD movie (mkv from a Blu-ray) and that’s the reason why it buffers after 20-30 seconds.
I knew that the DS923+ is not the best at transcoding, but since it worked to play 4K via Plex according to https://nascompares.com/ on the DS923+, but I thought that it wouldn’t be a risk for me, since I only have HD movies…
It should be a setting, right?
I’ve asked the same question to Synology support but haven’t received an answer yet.

After contacting Synology support, they claim that my problem lies in the Plex software, as it is easy to play movies from the NAS on the computer via the SMB protocol. (I use VLC player on the computer.)
However, I received an email from you the other day that you will now charge for your Media server software by “Remote Watch Pass”…
This all together results that I choose to change to Jellyfin instead, as I also avoid advertising for various movies and series from Plex.
Thanks for your help anyway…

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