I’m thinking to build for my home lab 4 small servers which will be installed on a rack
So I’m looking for a short 2U case, something that can accept ATX board (I’m planning to use Ryzen 5800 which has a 65W TDP). It should have a depth of around 40-60 cm.
While I can’t give specific recommendations for 2U chassis are you dead-set on 2U?
Was in a similar situation homelab-wise and landed on a few 4U SilverStone GD07, as far as I know the smallest footprint case that even handles E-ATX (tested with an ASRock X99 WS) and has space for numerous 120 mm fans for relatively quiet and efficient air cooling.
It’s very unusual to find standard ATX hardware that will even fit in a 2U case. Standard ATX power supplies can’t even fit in a 2U case unless they’re turned on their side, and with the way their exhaust fan is typically situated they will blow air either up or down in that configuration, right into your chassis and blocking airflow. Typically, you would want airflow through the chassis to intake through the front and exhaust out the back. Many CPU coolers also will not fit properly in a 2U chassis and even fewer will blow air sideways the way you want it rather than straight up. Expansion cards either have to be low-profile or they have to fit sideways, again not an ATX configuration. Chassis fans will have to be smaller and therefore rotate faster and make a lot more noise to move the same CFM through them vs. larger fans 120 and 140mm fans that will only fit in a 3U or 4U (or higher) case respectively.
Shorter cases exist but it leaves less room inside for your PSU, chassis fans, any drive bays you might want to have, etc. I have a really short depth case (about 30cm deep, meant for fitting in an audio or networking rack) but it’s 4U and the PSU is mounted above the motherboard since the mobo takes up just about all the room inside on the bottom.
What is your primary purpose for your homelab? Is your 2U limit all you have room for in your rack or could you go higher if needed? What will you be using the server for and will it need additional hardware (e.g. drives, etc) that you didn’t mention previously?