I listed dual/quad 8180 as a good option. I don't think you can get second hand 8180 on ebay.
For 1950x, details explanations were provided in my post -
1. too sloow, cinebench score is 3k, you can get it from 4-5 years old ancient processors already declared as EOL. 2. no official ECC support
I can list more actually - single socket system with 8 DIMMs only. As explained, it is a good platform for kids to game/overclock.