Actually, for about 1700 you have the Blackbird BK1B01 mainboard + cpu from Raptor, with 4 cores, 16 threads:
https://www.raptorcs.com/content/BK1B01/intro.htmlI bought two of these last year and they're great, stuff your own memory in there, add some storage and off you go.
Edit: clarified that this would be a mainboard + CPU.