Plex buffering issue with LG 55QNED86T6A

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fritzman

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#319803 4-Jun-2025 10:04

BACKGROUND

LG 55QNED86T6A TV Manufacture date is Feb 2024 and I use the Plex app on it to access (generally) 1080p TV & Movies which are on my Synology DS1819+ NAS running as Plex server (until I replaced the Plex server function with a NUC11TNH last month, also) in the garage.

My Internet is 2-degrees 300/100 to TP-Link X55 set to Router - DNS manually set to 8.8.8.8 and the router is set to reboot every morning, plus a wired X55 satellite in the lounge by the TV. TV/NUC/NAS all have static IP's and are all in the

Network is router cabled to Netgear Prosafe JGS524PE switch.

Connected via ethernet are: NAS, TV, NUC, Amcrest 5Mp POE camera, Amcrest 2Mp camera. 5Ghz WIFI connections are TV (disconnected the ethernet about 3 weeks ago) and 2 x iPhones.

I am now running the NUC only as the Plex server, and the NAS only as mapped storage.

PROBLEM

Until about 6 months ago, Plex worked flawlessly. No lagging/buffering. Since then, I am seeing more and more buffering. I figured the NAS was getting on a bit, and my research suggested I would get much better performance running the Plex server on a dedicated PC or NUC. Enter the NUC, but the problem persisted.

TESTING

My understanding is that despite being on the same network, Plex on the TV draws data via the web (please correct me if I'm wrong) so I ran speedtest and fast.com on the TV. I tested the TV wired to the satellite with the satellite X55 wired directly to the router, directly to the switch, and wirelessly to the router. I also tested the TV connected using 2.4Ghz and 5Ghz, connected to the satellite and also directly to the router.

Wirelessly directly to the router using 5Ghz gave the best results, so this is the way the setup currently is.

Since that time (maybe a week now), I am again seeing buffering occasionally, and sometimes the TV after just being turned on, when going into Plex or other Internet-based apps, will say Network unavailable.

On on occasion a few days ago, the TV was playing a show off the NAS and the dreaded circle started going around in Plex, buffering, so I grabbed my phone, opened Plex and hit resume, and the show resumed fine and kept playing fine.

It feels like the TV is struggling with the network.

QUESTIONS

I do have a spare 24-port switch (non-poe)... should I try that with Router>switch>NUC & NAS? The other traffic (cameras specifically) will obviously track through to the NAS still for recording (which I guess I could turn off to see if it makes a difference?).

Is my TV on the way out?

Have I missed anything?

Sons Rig: Asus TUF Gaming X-570, Ryzen 9 3900X, G.Skill neo 2x16Gb 3600's, Sabrent Rocket 1Tb M.2, Win10 Pro, Phanteks case, EVGA G5 850W.

NAS: DS1819+ - 52Tb in Raid6

My rig: HP Elitebook X360 Lappy with a 2Tb SN850.. woohoo.. I've retired!

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#3380390 4-Jun-2025 10:28

Are the Plex server and the Plex client on the same subnet? The client should connect to the server directly if on the same network.

Some clients are know for not supporting all codecs, and the server needs a GPU or it will use a lot of the CPU for decoding.

Are you doing decoding on the server or client? Have you tried changing the settings on the client to stream the content in native format, so decoding moves from the server to the clients?

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fritzman

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#3380394 4-Jun-2025 10:46

Thanks for the questions...

Are the Plex server and the Plex client on the same subnet? The client should connect to the server directly if on the same network.

Yes, both 192.168.1.xx

Some clients are know for not supporting all codecs, and the server needs a GPU or it will use a lot of the CPU for decoding.

Are you doing decoding on the server or client? Have you tried changing the settings on the client to stream the content in native format, so decoding moves from the server to the clients?

Decoding was on the NAS and it is now on the NUC (which came from doing the same job for another user) and is apparently quite a bit better than what is required. I haven't tried native, as I assumed that the NUC would be far better at transcoding than the TV.

Sons Rig: Asus TUF Gaming X-570, Ryzen 9 3900X, G.Skill neo 2x16Gb 3600's, Sabrent Rocket 1Tb M.2, Win10 Pro, Phanteks case, EVGA G5 850W.

NAS: DS1819+ - 52Tb in Raid6

My rig: HP Elitebook X360 Lappy with a 2Tb SN850.. woohoo.. I've retired!

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#3380396 4-Jun-2025 11:01

Some old TVs might not have the power or support the codecs. But you should try it.

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razor2000nz

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#3380409 4-Jun-2025 13:00

Are you able to try a different client? ie firestick/appletv/android tv device. To see if that will play better than the TV? Need to only change one thing at a time.

toejam316

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#3380410 4-Jun-2025 13:07

Do you have Plex Pass, and do you have hardware acceleration enabled? If the answer to either is no, that may be a contributing factor.

If you don't have Plex Pass, Emby and Jellyfin also have LG TV clients, possibly changing to one of those to test could be worthwhile?

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#3380417 4-Jun-2025 13:20

I have an "ancient" LG TV with the Plex app, and not experienced what you've described. Just using wifi to the TV.

Server is just an i5 6500 desktop.

Maybe try Emby/Jellyfin, and see if any different for testing purposes but I wouldnt go whole hog to a new ecosystem just yet until you're sure its a software and not hardware issue.

Also check your server usage stats when the buffering occurs and might find a certain process is kicking in.

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fritzman

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#3380429 4-Jun-2025 14:03

Thanks for the replies…

No other clients available to test on the TV, but as mentioned.. a show that stalled on the TV played straight away (while tge TV was still stalled) on my iPhone.
Plexpass is a yes, and yes, hardware acceleration is enabled as far as I understand.
Hmmm.. usage while playing on TV seems to hover around 3-5 or so Mb/s and there is the very occasional 10-12Mb/s leap.. not sure why. Am I talking about the same thing as you?

Sons Rig: Asus TUF Gaming X-570, Ryzen 9 3900X, G.Skill neo 2x16Gb 3600's, Sabrent Rocket 1Tb M.2, Win10 Pro, Phanteks case, EVGA G5 850W.

NAS: DS1819+ - 52Tb in Raid6

My rig: HP Elitebook X360 Lappy with a 2Tb SN850.. woohoo.. I've retired!

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gehenna

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#3380440 4-Jun-2025 14:34

Does the file in question even need to transcode? Is Direct Play enabled for files that require no transcoding? If not, you may be transcoding unnecessarily in the first place. You will also know if hardware transcoding is working correctly as the file will show (hw) at the end of its name in the playback Activity panel.

fritzman

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#3380487 4-Jun-2025 18:11

gehenna:

Does the file in question even need to transcode? Is Direct Play enabled for files that require no transcoding? If not, you may be transcoding unnecessarily in the first place. You will also know if hardware transcoding is working correctly as the file will show (hw) at the end of its name in the playback Activity panel.

Progress.. I hadn’t found that detail area in activity before.
Right now, plex on the TV is playing a 1080P movie, video & audio @ direct play @ 3Mbps. The TV is 4k btw.. I guess it’s either playing it at 1080p or doing the upscaling?

Sons Rig: Asus TUF Gaming X-570, Ryzen 9 3900X, G.Skill neo 2x16Gb 3600's, Sabrent Rocket 1Tb M.2, Win10 Pro, Phanteks case, EVGA G5 850W.

NAS: DS1819+ - 52Tb in Raid6

My rig: HP Elitebook X360 Lappy with a 2Tb SN850.. woohoo.. I've retired!

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gehenna

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#3380490 4-Jun-2025 18:24

If it's transcoding it'll say it's transcoding in the activity panel. If it's direct playing it'll say that too. Helps if you know the bitrate and resolution of your file to be sure how it should play. 3Mbps 1080p could easily be Direct Playing. Could just as easily be transcoding. You need to see what it says during playback in the Plex webapp, or on the Plex Dash mobile app. But what it won't be doing is upscaling to 4k. And don't forget, if your network is poor, 3Mbps will be coming off the top of your Wi-Fi bandwidth. The chonkier the file, the more you'll eat into your local network bandwidth so it also needs to be able to support the requirement.

shrub

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#3380561 4-Jun-2025 19:38

If its playing direct play then its a bandwidth issue. Either the TV cannot support the media(H.265/HEVC) / Network issues (try everything on a wired connection) / there is a dying HDD that cannot feed the data fast enough.

Also check for the (hw) if its not hardware transcoding then its going to smash the CPU. If its transcoding hardware then its possible HDR tone mapping or HEVC is too much for the NAS GPU.

Check the status page on the server in a web browser it will show what's happening and the buffer levels.

eg. this is a 4k HDR10 movie 48gb file size being HW transcoded and its barely touching the CPU so its smooth.

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shrub

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#3380564 4-Jun-2025 19:44

Sorry just looked up your NAS and its an Intel Atom C3538 which doesn't have intel quicksync so all transcoding will be done via CPU.

Suggest playing everything direct play only this can be done only the TV.

fritzman

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#3380720 5-Jun-2025 12:29

shrub:

Sorry just looked up your NAS and its an Intel Atom C3538 which doesn't have intel quicksync so all transcoding will be done via CPU.

Suggest playing everything direct play only this can be done only the TV.

Yep... the NAS was the Plex server, but is now only the mapped storage device.

Here is a screenshot of running a 4k movie (10Gb file) simultaneously on the TV and my AIO PC, both connected wirelessly to the local network. Both ran without glitches, so I'm wondering whether something has kicked in?

Sons Rig: Asus TUF Gaming X-570, Ryzen 9 3900X, G.Skill neo 2x16Gb 3600's, Sabrent Rocket 1Tb M.2, Win10 Pro, Phanteks case, EVGA G5 850W.

NAS: DS1819+ - 52Tb in Raid6

My rig: HP Elitebook X360 Lappy with a 2Tb SN850.. woohoo.. I've retired!

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fritzman

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#3380745 5-Jun-2025 15:02

Also.. I note in the Plex settings on the TV, the direct play option is ticked, but there is an option also to ‘force’ direct play, which I have not ticked too.
Not sure if this will apply to all future instances, or whether I need to do it for each item watched.

Sons Rig: Asus TUF Gaming X-570, Ryzen 9 3900X, G.Skill neo 2x16Gb 3600's, Sabrent Rocket 1Tb M.2, Win10 Pro, Phanteks case, EVGA G5 850W.

NAS: DS1819+ - 52Tb in Raid6

My rig: HP Elitebook X360 Lappy with a 2Tb SN850.. woohoo.. I've retired!

Heat under fritzman (152-0-0)

Basil12

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#3380856 5-Jun-2025 19:49

We use the Google TV Chromecast dongle for Plex on our main TV as it is a few years old. Every now and then the Plex app on the Chromecast needs to be reset: force stop, clear data, and then go through the plex.tv/link process.

I haven't had this issue with the two newer Samsungs running Plex, but thought I'd mention it in case it assists.

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