Plex using all of CPU

Plex Media Server NAS & Devices
1

Server Version#: 1.23.0.4438
Player Version#:

Synology Diskstation 412+, Plex is using CPU while idle and I cannot do anything.
I’ve disabled Video transcoding and thumbnails preview and I can’t figure out what’s using CPU.
I’ve tried installing again, same thing. I even upgraded RAM from 1GB to 4GB because Plex sometimes used a lot. I repeat, this is while idle, no movies are being streamed. Library is fully scanned, no sharing to other people.

How do I find out why is Plex using all that CPU? Could someone please help me figuring this out?

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2

It’s likely trying to transcode your video for playback.

In most cases on Synology, we see it max the CPU when it tries to burn in subtitles (which a Synology does not have the power for). This machine is VERY weak too in that regard.

To confirm what is happening:

  1. Settings - Server - General - Show Advanced

  2. Make certain DEBUG is enabled

  3. Make certain VERBOSE is disabled

  4. Click SAVE if you make any changes.

  5. Now start playback of anything which causes this and play for 20 seconds

  6. Stop Playback

  7. Wait 20 seconds for the log information to flush out to disk

  8. Settings - Server - Troubleshooting - Download Logs

  9. Upload (attach) the ZIP file it gives you here.

  10. I’ll review it and show what it’s trying to do with that video.

3

I’ve noted above, nothing is playing, nothing in dashboard. Idle. I’ve also disabled video transcode in Transcoder settings.

4

Logs please?

I still need to see what it’s doing

5

Sorry about my late reply, I was trying to figure out when this happens exactly. I think I’ve figured it out and that this is happening when I’m browsing through the movie library on my PC or on my TVs. The library is scanned and looks like it is loading thumbnails. Is there a way to make Plex do that while idle or something?

I’ve also attached logs…Plex Media Server Logs_2021-05-02_14-41-05.zip (3.8 MB)

6

Thanks for the logs.

They confirm what I’ve suspected since your initial post.

The DS412+ is getting too old to be a Plex server.

It only has a D2700 CPU (dual core - 438 Passmarks of performance)

The minimum, as of 4 years ago, is 700 Passmarks for the typical good experience.

What do you have which you can move the server itself to but let the Syno continue to be the solid NAS it is ?

7

hi @ChuckPa ,

thank you for looking into it. I have a core i5 PC which is more than capable of handling any Plex task but my initial idea was to have something which is always on and I don’t have to turn on the PC just for watching videos. (I’m running Plex server on both btw.)

thanks again, I will think about my options.

9

Okay, this makes absolutely no sense.

Let me provide some more details:

  • This CPU usage spike happens while browsing the Media library, not watching a movie and only when the client player needs to render thumbnails for library content

  • All content is direct played, not transcoded

  • This was working roughly two months ago, normally streaming 4K HDR content

So now, all that comes to my mind is the RAM upgrade from 1GB to 4GB which happened roughly at the same time.

11

Nope.

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Also, Disabled Video transcoding so those HDR settings should not have any effect either…

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