Help with New Build HTPC

[Sir Topham Hatt]

I currently have a low ability PC that holds 4-6 hard drives, one SSD the rest traditional HDDs that's connected to my TV via HDMI.

It's probably an Intel i3 or i5 with a non-fan graphics card, on board 5.1 sound.  It did struggle to run a 4K film, which is a shame but I'd be looking at upgrading to be able to play them if possible.

It's running Windows 10 Pro with Plex.  Whenever we want to watch something we have stored, we just push the power button and use the Plex app on the TV.  I only really "see" Windows when I'm copying data as I can't get it to talk to my other PC through the network.

 

I was wondering whether something like a Synology would be better? (in terms of size and sound - although the case I have is pretty quiet anyway.)

If I bought a Synology, am I right in thinking it would come with a bit of storage for an OS on the motherboard? I wonder if these new fangled NVMe boards could also work for the OS instead of a drive?

We don't have the PC on all the time so don't need it to be proper NAS but do need capacity and perhaps will be adding to it in the future.

Thanks