1. Stick with DDR4 systems, DDR3 are much slower. 2. Used to have both 1U and 2U servers at home, as people mentioned they are pretty loud, try to avoid 3. Regular commodity tower case with slots for 120 fans is best in terms of loudness/cooling capabilities 4. Try build something on commodity hardware pieces - would be easier to sell it away once you want to get rid of it.