UPDATE: Decided on the TVS-951x (planning on getting a new TS-453Be)

[janwer]

So Apple TV 4K with Plex client or any other box with Plex client will do the heavy work of transcoding without HW acceleration in Qnap TS-873?
I want to transcode 4K to 4K with subtitles.

[Trexx]

So what is advantage of TVS-951x over TS-873? With which should I upgrade from my TS-251A?

Biggest advantage of TVS-951x is the embedded GPU that is supported by Plex for HW Transcoding and 10GbE out of the box. The CPU is slower in the 951x, so for things like VM's and such the 873 will be faster.

Other things are somewhat a trade off. You get the embedded m.2 SATA SSD's on the TS-873 vs. 2.5" drive bays on the TVS.

[Trexx]

So Apple TV 4K with Plex client or any other box with Plex client will do the heavy work of transcoding without HW acceleration in Qnap TS-873?
I want to transcode 4K to 4K with subtitles.

See the answer I gave you on the Plex forum (specifically the 1st link re: direct play and the callout re: subtitles). If it has to "burn-in" the subtitle, you are toast in regards to 4k (not enough CPU).

The AppleTV 4k is a good device, or the Nvidia ShieldTV is also a monster for 4k as well. Just depends how deep into the Apple ecosystem you are, but with Movies Anywhere even that is becoming less of an issue.

[janwer]

My understanding now it's not possible to transcode 4K to 4K with TVS-951x because it can decode 4K and encode only 1080. Transcoding is decoding and encoding. So what advantage can I have with TVS-951x with 4K UHD files and 4K UHD Apple TV over TS-873?
In this table https://docs.google.com/spreadsheets/d/ ... 1274624273
there is no 4K transcoding for TVS-951x. Only "some" and "decode only". No transcoding for 4K! No green box with "yes" inside in 4K column.

[dolbyman]

well not quite sure that matrix is correct

the intel hd 610 supports 4k hevc 10 bit hardware de- and encoding

https://en.wikichip.org/wiki/intel/hd_graphics_610

[janwer]

What are the options for graphic PCIe card for TS-873 and transcoding? Is it possible?
TS-873 is perfect for me except no HW transcoding which I don't know yet if I'll need it. No use for 10Gbps in near future and having 8 3,5 bays give me more flexibility.