Yesterday Evening I replaced my HP z240 that was sitting on a shelf with a Rosewill 2U 15" chassis (center image)
TheRosewill machine is an AMD 4, Ryzen 5 5600X @3.7Ghz with 6-core/12-threads. 32 GB (4x 8GB) of DDR4 DIMMS. A B550M AORUS ELITE microATX board. With a 1TB NVMe SSD, NVIDIA Quadro P1000 for PLEX transcoding and lastly a SFP+ 10gig network card. I also replaced the stock MOLEX fans with Noctua redux PWM fans.
The upgrade was primarily to satisfy my OCD and get the “PC on a shelf” replaced with an actual rack mounted computer. The AMD cpu is a bit more powerful than the previous intel i7-7700 and can run the minecraft hosted worlds a bit smoother, and doesn’t interfere with PLEX serving or transcoding at all.
Both the PLEX server and synology data storage server are linked with 10 gig through the 10gig Unifi X16 switch.
The entire setup is inside of a 18U wall mounted and enclosed rack mount with four 120mm fans for ventilation on the top and bottom.
Rack explained top to bottom: U1 - Unifi-8p-60W switch for PoE to my two Unifi-IW-AC units.
U2 - Keystone Patch Panel for inter-rack connections and connections throughout house.
U3 - Unifi-X16-10G switch (12 SFP+ ports and 4 8P8C ports, all with 10Gig speeds)
U4 - vented blanking panel with 4x 80mm USB fans for added cooling
U5 - Unifi Dream Machine Pro with 4TB internal HDD for recording
U6-8 - Shelf holding my Modem and MoCA adaptor and assorted power bricks
U9 - Blank panel
U10-11 - new Rosewill 2U chassis
U12 - vented blanking panel
U13-14 - Synology RS1221+
U15 - blank panel
U16-17 - Cyberpower UPS
U18 - PDU
To just get started I’d take a trip to your local thrift store. Some decent old PC tower and a large harddrive is more than enough to get started, play around and get it working. Opt for an intel CPU with “quicksync” if you can as it will do hardware trans coding without a dedicated GPU (like I have).