I’m wondering about this Plex setup: if I have a capable mini PC running PMS, then how much does the RAM matter for the accompanying NAS if It is just file storage? Second, I have heard that USB 3.0 is inferior to a NAS but I wanted to check if this was true. Would a DAS function just as well as a NAS for Plex media storage? Thanks in advance for your help! God Bless!
I can only tell you this much:
A NAS does use its own RAM for file caching. Which means if you are accessing the same file repeatedly, it is still transmitted over your network repeatedly.
(At least that is the behaviour when using Windows to access the file server/NAS.)
So you can benefit from your NAS having plenty of RAM.
If your NAS is combining several hard drives into an array, you want plenty of RAM in it anyway. If you are using drive arrays, don’t skimp on RAM size.
If you are attaching a DAS to your computer, the file cache is of course provided by the main RAM of the host computer. Which does mean that you should have plenty of RAM in it. If this machine is not only used as a Plex server, but also as a file server or for curating/transcoding/muxing your media files, you get the biggest effect if you have at least as much RAM in it, as your largest media file is big. (Ideally, even a bit more than that.)
The general speed of a DAS is largely depending on the converter chips used in it, which adapt USB to SATA. It can be fast, it can be sluggish. That is all down to the particular model.
You should do your research and pick a DAS model with good experience reports by actual customers. (i.e. not those fake reports which some shops generate with AI or “rent-a-reviewer” services)
Extremely helpful. Thanks so much for taking the time to respond, Otto! Greatly appreciated 
