I have been in contact with QNap support and this is thier last response to this issue:
" Support Team
2020-02-11 18:23:57
Hi Oscar, I checked with the PM, and you currently cannot use it. They have removed this limitation in firmware 4.4.2 so you will be able to use external GPU for transcoding in 4.4.2 firmware in the future."
(In the context of supporting hardware transcoding in Plex in a TVS-x73e NAS)
I have just updated my TVS 873 to QTS 4.4.2 and my NVidia drivers to 3.0.5 (418.56 driver version), and Plex still canāt use my P400 for transcoding. Any idea why, @ChuckPa ?
Perform a restart of Plex please (making sure you have DEBUG logging on, VERBOSE off first)
Next attempt to transcode something (about 30 seconds worth).
Letās see what it returns. (Logs ZIP)
Iām sorry. thatās not usable. Transcoder statistics are meaningless at this point.
Please provide the full logs.
@ChuckPa , is there a way to send you without making it public on the web? Iām a bit wary for privacy reasons.
Hello
I have a TSV-873E and I wish purchase a good GPU card to add in my Qnap but I want feedback about the best compatible card I should purchase. The only usage for this card is to enable hardware transcoding with Plex.
I read someone use P200 and other GTX-1050, but I need recommendation for purchasing the GPU with best higher performance.
Thanks
@marcmale, I have a TVS873e and have not yet been able to use my Quadro P400 for transcoding with Plex (have been doing with other alternatives for a while now), so it is not guaranteed that you will be able to do it if you get a new GPU.
If you decide to get one, your options are pretty much GTX1050, Quadro P400 and Quadro P2000. While the first two ones would behave in a similar fashion when it comes to transcoding, the P2000 is not limited to two simultaneous transcodings, so you would have a potentially more powerful solution.
Of all upgrades I have done to my system, however, adding a WD Blue 1Tb M.2 gave me the greatest improvement in overall performance (Plex libraries load much faster)
Before I order a P2000, did someone manage to make transcoding work with Plex? When I look at the GPU card compatibility table for a TS-873 (similar model), only the GTX-1050 does transcoding. The others are only used for virtualization and I donāt understand why? There is limitation on some Nvidia card?
Ignore worrying about QTS showing HW transcoding, because QNAPs HW transcoding has nothing to do with Plexās HW transcoding.
As long as it says HD Station, that is all you need. HD Station means it has support via Nvidia Driver bundle, which is what Plex relies on for HW transcoding (besides having to have Plex Pass subscription).
Make sure you are on QTS 4.4.2.x build because Plex v1.17+ requires newer Nvidia drivers that are only available under QTS 4.4.2.
Thanks for the update .
Have you managed to make Plex transcoding work with the new drivers?
Several people on the forum mention that it does not work even with the new driver.
I believe I did a quick test and it showed them working but I can double check tomorrow.
@MwC_Trexx, Are you talking about a TVS X73? My TVS-873 doe snot allow the GPU to be in any mode other than container station. Yet, Emby manages to use it for transcoding, as I reported above. Just tested again with the latest versions of QTS, Nvidia & PMS.
The catch is in the āsimilarā they do have differenbt capabilities when it comes to GPU support.
For me, the only alternative for support for the Quadro P400 is for the container station, and yet it is not mentioned anywhere in the documentation.
@pcamargo No, I was only referring to the TS-x73 family w/GPU. There are ways (with work) that potentially the GPU can be leveraged with a docker container, but those would be unsupported by Plex.
See here for a method that MIGHT work. https://gist.github.com/weshofmann/620b924cde5dd498880e9315e48e793b
Makes sense. It is just that topic is about the TVSx73 series of NAS
And what about the TVS-x73? I have been able to use my Quadro P400 for transcoding with Emby for several months now, but no dice with Plex. It was promised with the new versions of the NVidia drivers, but it did not happen.
Is better HW transcode support in docker something that Plex is looking at? I would like to be able to use it without hacking too much. 
Plex HW transcoding with Nvidia via native QPKG requires 2 pieces:
Is your P400 card listed via the QTS > Control Panel > Hardware > Expansion Cards as being in QTS mode?
If it is not listed, then Plex will not be able to leverage it as it checks for that during Plex startup.
If it is listed, then we would need server logs to see if other conditions that Plex checks for have been met.
That I donāt have any insight on, but @ChuckPa might.
