I’m looking into having a home server with the idea of storing music, pictures and movies and with the capability of viewing the movies on my TV. I have a Roku stick and hope to use that to access the NAS or server. I have watched a few videos about the QNAP TS-251D and think it may be the machine for me, but I know there are others out there. I think my biggest worry is making sure I have the ability to have multiple people accessing the server on multiple TV screens or being able to access it from outside my home network and not run into the issue of the processor or RAM not being sufficient. I have also looked into the TS-x53Be Series from QNAP and wonder if it is a better option with the Quad processor? Or is the TS-453Be a better option? I understand the 53Be models have the 4-bay, but as I mentioned, my concern would be the processing power and not having a lag while watching movies.
Qnap TS-251D is indeed their latest model with up to date hardware inside. It is capable of transcoding 4K and several FHD streams simultaneously. But TS-453Be and 253Be feature 4 cores allowing to transcode even more streams. Qnap x53be series feature J3455 CPU with a benchmark score 2132 which is around 30% faster then 251D with score 1552.
Even though Qnap TS-251D feature newer graphics chip, the TS-253Be can handle mode video formats. Very important difference is H265 10bit decoding. This is popular standard for new 4K TVS with an HDR support.
I hope this helps.