Previous post: https://monero.town/post/279294
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.
This is awesome, surprised that you have this low of a ROI. When I looked for parts a year or two ago I couldn't get lower than 4,5 years and that might have been with free power :P
I live in a US suburb, electricity is thankfully cheaper than most places. As detailed in my first post, I could've cut a lot more corners to cut down on costs.
I think electricity is a major factor though, roughly 1/4 of my earnings go to it. Many places have much pricier electric which will easily add years, if not making roi impossible.