Finished building and setting up my 4 3900 builds, read my previous post for more details.
Figuring out the best way to build them into the shelf was a lot of trial and error, especially with cable management. Took a few hours, but I'm glad it worked out in the end.
I was satisfied with my undervolt on the first rig, but unfortunately I was not able to transfer it to the second. I ended up just using dcop and keeping all the cpus stock for uniformity instead of individually overclocking all the machines.
Right now they're doing 12.2-12.4kh/s at 80-84c which is making the room quite toasty, should be nice in the winter (not so much in the summer). Would ROI in about 3 years at the current rate.
The top machine is a 5600x which I use as a home server, running monerod and p2pool. I used to run nixos but I eventually switched back to alpine like the other 5 machines. Currently using docker-compose and nixery.
Sorry the text is so dense, feel free to ask questions.