This is a build I've been meaning to post here for a while.
This is extremely tiny, just the width of the motherboard and about 100mm longer for the fans and the front panel. 115mm tall, including the feet. The top of the fan is only 2.5mm from the inside of the top lid (which has perforations for air).
I do need to move the power supply further away.
Application is digital transport for an audio system. Runs Daphile (dedicated audio OS). Basically a 5600G with HT disabled to keep power consumption down, will also try disabling cores to find the correct balance. Currently OS is running off a pendrive, have only recently freed up a M.2 drive for it for migration. Daphile allows migration within the main OS and no cloning software is needed for the move.
Pretty quiet except when upsampling to DSD, where it emits an audible thrum when the lid is closed due to the case vibration. It's better with the lid off, so I need to track down the source of case vibration. Airflow is a bit iffy because there's no real way around the RAM, but CPU maxes out at 65C with the Noctua LH-9A. The case was never designed for this sort of heatload, so there's that.
Motherboard is the Asrock B550 ITX with 16GB of 3200C16 Corsair LPX (no other memory will fit). Power supply is a Pico-PSU clone - 160W claimed capability, sourcing DC from a Meanwell LRS 200-12. Both the Pico PSU and case were imported directly before the current block on imports from China. The case was bought in 2010, and the PSU in 2016 sometime.