Prefacing this post to note that My first build from a JDM_WAAAT post was the NAS Killer v2.0 in July/Aug 2018 and it’s still chugging along as my main Proxmox server.
I had my NAS as a VM running Open Media Vault and finally decided I really needed to get a proper NAS built. I had my eye on NAS Killer 6.0 from when it came out but only recently had the resources to jump on it. As many are aware I’m sure, most of the listed motherboards are in short supply and expensive now so based on the basic criteria along with some of my own requirements, I built the following:
Mobo:
ASROCK Z390M Pro4 - $96.00
Missed one for $20 cheaper but ended up with a new in box mobo 
CPU:
Intel i7-8700 3.2GHz 6 core - $80.00
RAM:
Silicon Power Value Gaming DDR4 RAM 32GB (2x16GB) 3200MHz - $52.00
PSU:
EVGA 600W 80 Plus - $49.00
Cooler:
Thermalright Assassin X120 Refined SE - $20.00
HBA:
Adaptec - ASR-7805 - $25.00
Boot Drive:
WD Blue 1TB SN580 NVMe Internal SSD - $62.00
Cables:
2 x SFF-8643 → SATA/SAS breakout - $36.00
2 x SATA power splitter - $13.00
Misc:
fan for HBA - Noctua NF-A4x10 FLX, Premium Quiet Fan - $14.00
Case:
Fractal Design Node 804 Micro-ATX Computer Case (Windowed, Black) - $125
HDD:
Already had 8 7 HDD of varying sizes already used with my OMV VM. (one died somewhere along the way)
TOTAL:
$572.00
*I wanted to note about the case choice. First, I obviously needed a case that could hold my drives without having to mod it. The Node 804 will hold 10 x 3.5" HDD + 2 x 2.5" HDD/SSD.
Second. Having built my last two desktop PCs using good quality cases instead of cheaping out to save some $$, I found that in most cases the extra money is very well worth it for the build quality of the case. They are a real pleasure to build in and they will last much longer.
Future plans:
- I want to add at least a 2.5Gb network adapter on this along with my pfSense router and server (pc already has 2.5gb NIC
- More RAM eventually
- Bigger HDDs
For all of you that I’m sure will say, "You should switch to UnRaid/TrueNAS/etc.
I considered switching to UnRaid but converting my mergerfs/snapraid array to UnRaids file system is too much of a pain right now and I’m already comfortable with OMV. I also don’t use the docker feature since I have a server for that.
TrueNAS, etc, I already have a bunch of different size drives and don’t want to spend the money in a bunch of new, 10+TB drives. Besides, with my current config, my whole NAS could fail and as long as the HDD are still good I can access each individually to access the files.