Ryzen is 100000% the way to go. In fact, I'm upgrading my FreeNAS server and have it almost completed. Ryzen is great because it supports ECC RAM (Asrock and Asus tend to have the best support) which ideally you should use for a NAS. You also get high core counts for cheap unlike Xeon, so you can run plenty of VMs and still have the horsepower to do a lot of Plex transcoding. You should REALLY consider ECC RAM in a NAS, and the pricing isn't terrible like it used to be especially on the model you'll see I used below. My upgraded server is as follows:
3U SuperMicro 933T-R760B (got on eBay around $300)- backplane has 15 hot swappable SATA ports on the front and 3 PSUs with redundancy so that if one fails it will still keep running
Asrock X370 Taichi- great board for a NAS since it is one of the few that has 10 SATA ports, so you might not need a dedicated RAID/HBA card. Superb hardware quality with 12k capacitors, strong VRM, and outstanding ECC support. Also supports hotswapping SATA drives which probably most boards do this, but some lower end may not.
Ryzen 1700- great because it's 8core/16 thread and reasonably priced, and has ECC support. Depending on current pricing and your needs you could go with a Zen+ like 2600 or 2700 if they go on sale.
4 x 16GB CT16G4WFD8266 ECC RAM- it POSTed first time with all 4 slots at 2666mhz with ECC enabled. I highly recommend this RAM as it's not super pricey. If your usable storage is 30TB or less 32GB of RAM should be enough. Just make sure to run in pairs of two because Ryzen is finicky with odd number of ECC and you probably won't get it working right
10 x 5TB Toshiba X300 hard drives- not the best for a NAS but I'll have plenty of redundancy in case they fail. Hard drive choice is up to you, NAS/Enterprise hard drives are usually a much better choice but I couldn't pass these drives up as they regularly go on sale for $99.99 (currently on Newegg right now)
Visiontek HD5450- just used for initial setup basically. After setup I just SSH into it for management or use FreeNAS webgui.
Two random flash drives for the OS. FreeNAS does little writing to the drives except for configuration and updates. I've used this setup for about two years in my current FreeNAS (specs under my signature) and had one fail- super easy to replace and rebuild the redundancy
Also my last words of wisdom: DO NOT use unRAID. It's proprietary, based on Linux yet doesn't support ZFS (which Debian and other distros have supported for a while now) and can only use btrfs/xfs. ZFS is superior in every manner and BSD licensing / any open source type licensing is better than proprietary. I'd highly recommend FreeNAS since it's based on FreeBSD which is rock solid, great for jails (kinda like isolated containers similar to FreeBSD VMs with direct hardware access and no overhead) and even great for VMs with Bhyve. I run two Ubuntu server VMs (Unifi controller and PiHole), a Windows VM for messing with things, and a bunch of FreeBSD "jails" and it is rock solid. Never goes down unless I reboot for updates. The SMB/NFS shares work rock solid. Even if you aren't keen on FreeBSD/FreeNAS, do something other than UnRAID like Proxmox. Here is a great guide on using ZFS filesystem under Proxmox, which is open source and not proprietary like unRAID: https://forum.level1techs.com/t/how-...ictures/117375
. ZFS has so many benefits compared to everything else and once you use it you'll never want to use anything else.