I want to get best NAS for Plex Server, because !

I need to say this …

I just got the DS718+ and its terrible NAS compares to ReadyNAS (Netgear) I had which is :
https://www.amazon.com/gp/product/B015S0Y50M/ref=oh_aui_detailpage_o09_s00?ie=UTF8&psc=1

but plex works so smooth and quick when it comes to updates media files and episodes .

with DS718+ I played the one tv show i mention and guess what played it only 20 seconds and CPU went red 97% and stopped playing … how the company says stream 4K media …

then I choose ( Use hardware acceleration when available ) but it reduced the video quality in terrible way

I got return this if possible