buy a server using aliexpress and used parts on ebay.
specifically, you can buy motherboards that let you overclock xeons or run them on turbo 24/7
look at this guys youtube channel for that topic, he reviews chinese hacked motherboards: https://www.youtube.com/watch?v=g1hC4Tr9-yM
this also can remove the shit the CIA uses to spy on you (Intel ME) so that's useful. For RAM you can usually buy used server parts from ebay. This way you can have way faster than most peoples destop PC with like 256gb ram for $400